diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..908ae16
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,24 @@
+root = true
+
+[*]
+charset = utf-8
+insert_final_newline = true
+end_of_line = lf
+trim_trailing_whitespace = true
+
+[*.{swift,swift.gyb,cpp,h,yml}]
+indent_style = space
+tab_width = 4
+indent_size = 2
+
+[*.{sh,py}]
+indent_style = space
+indent_size = 4
+
+[.swiftci/*}]
+indent_style = space
+indent_size = 4
+
+[*.{md,txt}]
+indent_style = space
+indent_size = 2
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 4902e36..f2be977 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -8,6 +8,9 @@ jobs:
   tests:
     name: Test
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
+    with:
+      linux_exclude_swift_versions: '[{"swift_version": "5.8"}, {"swift_version": "5.9"}, {"swift_version": "5.10"}, {"swift_version": "6.0"}]'
+      windows_exclude_swift_versions: '[{"swift_version": "5.9"}, {"swift_version": "5.10"}, {"swift_version": "6.0"}]'
   soundness:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
@@ -16,3 +19,5 @@ jobs:
       license_header_check_enabled: false
       unacceptable_language_check_enabled: false
       format_check_enabled: false
+      api_breakage_check_enabled: false
+      docs_check_enabled: false
diff --git a/.gitignore b/.gitignore
index c213bfa..286e2a2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,5 @@
 /*.xcodeproj
 xcuserdata/
 /Results
+/Documentation/Example/.build
+/Documentation/Example/Package.resolved
diff --git a/.spi.yml b/.spi.yml
index e492387..6398aa8 100644
--- a/.spi.yml
+++ b/.spi.yml
@@ -1,4 +1,4 @@
 version: 1
 builder:
   configs:
-    - documentation_targets: [CollectionsBenchmark]
\ No newline at end of file
+    - documentation_targets: [CollectionsBenchmark]
diff --git a/.swiftpm/configuration/Package.resolved b/.swiftpm/configuration/Package.resolved
new file mode 100644
index 0000000..d874c62
--- /dev/null
+++ b/.swiftpm/configuration/Package.resolved
@@ -0,0 +1,25 @@
+{
+  "object": {
+    "pins": [
+      {
+        "package": "swift-argument-parser",
+        "repositoryURL": "https://github.com/apple/swift-argument-parser",
+        "state": {
+          "branch": null,
+          "revision": "41982a3656a71c768319979febd796c6fd111d5c",
+          "version": "1.5.0"
+        }
+      },
+      {
+        "package": "swift-system",
+        "repositoryURL": "https://github.com/apple/swift-system",
+        "state": {
+          "branch": null,
+          "revision": "d2ba781702a1d8285419c15ee62fd734a9437ff5",
+          "version": "1.3.2"
+        }
+      }
+    ]
+  },
+  "version": 1
+}
diff --git a/.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark-Package.xcscheme b/.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark-Package.xcscheme
deleted file mode 100644
index 53d0ac4..0000000
--- a/.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark-Package.xcscheme
+++ /dev/null
@@ -1,91 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Scheme
-   LastUpgradeVersion = "1250"
-   version = "1.7">
-   <BuildAction
-      parallelizeBuildables = "YES"
-      buildImplicitDependencies = "YES">
-      <BuildActionEntries>
-         <BuildActionEntry
-            buildForTesting = "YES"
-            buildForRunning = "YES"
-            buildForProfiling = "YES"
-            buildForArchiving = "YES"
-            buildForAnalyzing = "YES">
-            <BuildableReference
-               BuildableIdentifier = "primary"
-               BlueprintIdentifier = "CollectionsBenchmark"
-               BuildableName = "CollectionsBenchmark"
-               BlueprintName = "CollectionsBenchmark"
-               ReferencedContainer = "container:">
-            </BuildableReference>
-         </BuildActionEntry>
-         <BuildActionEntry
-            buildForTesting = "YES"
-            buildForRunning = "YES"
-            buildForProfiling = "NO"
-            buildForArchiving = "NO"
-            buildForAnalyzing = "YES">
-            <BuildableReference
-               BuildableIdentifier = "primary"
-               BlueprintIdentifier = "CollectionsBenchmarkTests"
-               BuildableName = "CollectionsBenchmarkTests"
-               BlueprintName = "CollectionsBenchmarkTests"
-               ReferencedContainer = "container:">
-            </BuildableReference>
-         </BuildActionEntry>
-      </BuildActionEntries>
-   </BuildAction>
-   <TestAction
-      buildConfiguration = "Debug"
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES">
-      <Testables>
-         <TestableReference
-            skipped = "NO">
-            <BuildableReference
-               BuildableIdentifier = "primary"
-               BlueprintIdentifier = "CollectionsBenchmarkTests"
-               BuildableName = "CollectionsBenchmarkTests"
-               BlueprintName = "CollectionsBenchmarkTests"
-               ReferencedContainer = "container:">
-            </BuildableReference>
-         </TestableReference>
-      </Testables>
-   </TestAction>
-   <LaunchAction
-      buildConfiguration = "Debug"
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      launchStyle = "0"
-      useCustomWorkingDirectory = "NO"
-      ignoresPersistentStateOnLaunch = "NO"
-      debugDocumentVersioning = "YES"
-      debugServiceExtension = "internal"
-      allowLocationSimulation = "YES">
-      <CommandLineArguments>
-         <CommandLineArgument
-            argument = "library run test"
-            isEnabled = "YES">
-         </CommandLineArgument>
-      </CommandLineArguments>
-   </LaunchAction>
-   <ProfileAction
-      buildConfiguration = "Release"
-      shouldUseLaunchSchemeArgsEnv = "YES"
-      savedToolIdentifier = ""
-      useCustomWorkingDirectory = "NO"
-      debugDocumentVersioning = "YES">
-   </ProfileAction>
-   <AnalyzeAction
-      buildConfiguration = "Debug">
-   </AnalyzeAction>
-   <ArchiveAction
-      buildConfiguration = "Release"
-      revealArchiveInOrganizer = "YES">
-   </ArchiveAction>
-   <InstallAction
-      buildConfiguration = "Release">
-   </InstallAction>
-</Scheme>
diff --git a/.swiftpm/xcode/xcshareddata/xcschemes/CollectionsBenchmark.xcscheme b/.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark.xcscheme
similarity index 94%
rename from .swiftpm/xcode/xcshareddata/xcschemes/CollectionsBenchmark.xcscheme
rename to .swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark.xcscheme
index 78cad2d..02a0d53 100644
--- a/.swiftpm/xcode/xcshareddata/xcschemes/CollectionsBenchmark.xcscheme
+++ b/.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark.xcscheme
@@ -1,10 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1250"
+   LastUpgradeVersion = "1600"
    version = "1.7">
    <BuildAction
       parallelizeBuildables = "YES"
-      buildImplicitDependencies = "YES">
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
       <BuildActionEntries>
          <BuildActionEntry
             buildForTesting = "YES"
@@ -27,7 +28,7 @@
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
-      codeCoverageEnabled = "YES">
+      shouldAutocreateTestPlan = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">
diff --git a/Package.resolved b/Package.resolved
index 018829f..bf10441 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -1,25 +1,24 @@
 {
-  "object": {
-    "pins": [
-      {
-        "package": "swift-argument-parser",
-        "repositoryURL": "https://github.com/apple/swift-argument-parser",
-        "state": {
-          "branch": null,
-          "revision": "9f39744e025c7d377987f30b03770805dcb0bcd1",
-          "version": "1.1.4"
-        }
-      },
-      {
-        "package": "swift-system",
-        "repositoryURL": "https://github.com/apple/swift-system",
-        "state": {
-          "branch": null,
-          "revision": "025bcb1165deab2e20d4eaba79967ce73013f496",
-          "version": "1.2.1"
-        }
+  "originHash" : "fd8098c511befeb09e71e5c075df627eb95b2e9614a53e9c75cc58a439abf5ec",
+  "pins" : [
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
+        "version" : "1.5.0"
       }
-    ]
-  },
-  "version": 1
+    },
+    {
+      "identity" : "swift-system",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-system",
+      "state" : {
+        "revision" : "a34201439c74b53f0fd71ef11741af7e7caf01e1",
+        "version" : "1.4.2"
+      }
+    }
+  ],
+  "version" : 3
 }
diff --git a/Package.swift b/Package.swift
index ef72721..43e581f 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,9 +1,9 @@
-// swift-tools-version:5.3
+// swift-tools-version:6.1
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -17,28 +17,21 @@ import PackageDescription
 // To use enable them, uncomment the corresponding lines or define them
 // from the package manager command line:
 //
-//     swift build -Xswiftc -DUSE_FOUNDATION_DATE
-var settings: [SwiftSetting]? = [
-
-  // On Apple platforms, measure time using Foundation's `Date` instead of
-  // the default method. This is useful when you want to run benchmarks
-  // on an operating system that predates the introduction of the function
-  // this package would otherwise be using.
-//  .define("USE_FOUNDATION_DATE"),
+//     swift build -Xswiftc -DSOME_SETTING
+let settings: [SwiftSetting] = [
+  .enableUpcomingFeature("MemberImportVisibility"),
+  .enableUpcomingFeature("StrictConcurrency"),
 ]
 
-// Prevent SPM 5.3 from throwing an error on empty settings arrays.
-// (This has been fixed in 5.4.)
-if settings?.isEmpty == true { settings = nil }
-
 let package = Package(
   name: "swift-collections-benchmark",
+  platforms: [.macOS(.v15), .iOS(.v18), .watchOS(.v11), .tvOS(.v18), .visionOS(.v2)],
   products: [
     .library(name: "CollectionsBenchmark", targets: ["CollectionsBenchmark"]),
   ],
   dependencies: [
-    .package(url: "https://github.com/apple/swift-argument-parser", from: "1.1.4"),
-    .package(url: "https://github.com/apple/swift-system", from: "1.2.1"),
+    .package(url: "https://github.com/apple/swift-argument-parser", from: "1.5.0"),
+    .package(url: "https://github.com/apple/swift-system", from: "1.4.2"),
   ],
   targets: [
     .target(
diff --git a/Sources/CollectionsBenchmark/Basics/Duration+Basics.swift b/Sources/CollectionsBenchmark/Basics/Duration+Basics.swift
new file mode 100644
index 0000000..f17c6ea
--- /dev/null
+++ b/Sources/CollectionsBenchmark/Basics/Duration+Basics.swift
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Collections open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+extension Duration {
+  // Backported from Swift 6.2
+  internal init(_attoseconds: Int128) {
+    self.init(_high: _attoseconds._high, low: _attoseconds._low)
+  }
+
+  // Backported from Swift 6.2
+  internal var _attoseconds: Int128 {
+    Int128(_low: _low, _high: _high)
+  }
+
+  // Backported from a utopistic future
+  internal var _seconds: Double {
+    Double(_attoseconds) / 1e18
+  }
+}
diff --git a/Sources/CollectionsBenchmark/Basics/Measurement.swift b/Sources/CollectionsBenchmark/Basics/Measurement.swift
index 72d938d..c7a6328 100644
--- a/Sources/CollectionsBenchmark/Basics/Measurement.swift
+++ b/Sources/CollectionsBenchmark/Basics/Measurement.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,7 +11,7 @@
 
 /// A point in the document coordinate system, i.e., a pair of size and
 /// time values.
-public struct Measurement: Hashable, Codable {
+public struct Measurement: Sendable, Hashable, Codable {
   public let size: Size
   public let time: Time
 
diff --git a/Sources/CollectionsBenchmark/Basics/Sample+Statistic.swift b/Sources/CollectionsBenchmark/Basics/Sample+Statistic.swift
index 2030736..ec1d80a 100644
--- a/Sources/CollectionsBenchmark/Basics/Sample+Statistic.swift
+++ b/Sources/CollectionsBenchmark/Basics/Sample+Statistic.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -12,7 +12,7 @@
 import ArgumentParser
 
 extension Sample {
-  public enum Statistic: Hashable {
+  public enum Statistic: Sendable, Hashable {
     case maximum
     case sigma(Int)
     case mean
@@ -25,7 +25,7 @@ extension Sample {
     case .maximum: return maximum
     case .sigma(let n):
       guard let sigma = standardDeviation else { return nil }
-      return Time(mean!.seconds + Double(n) * sigma.seconds)
+      return .seconds(mean!.seconds + Double(n) * sigma.seconds)
     case .mean: return mean
     case .minimum: return minimum
     case .none: return nil
diff --git a/Sources/CollectionsBenchmark/Basics/Sample.swift b/Sources/CollectionsBenchmark/Basics/Sample.swift
index e2304b8..9766357 100644
--- a/Sources/CollectionsBenchmark/Basics/Sample.swift
+++ b/Sources/CollectionsBenchmark/Basics/Sample.swift
@@ -2,14 +2,16 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
-public struct Sample: Equatable {
+import Foundation // For String(format:)
+
+public struct Sample: Sendable, Equatable {
   // Sorted array of measured durations.
   internal var _times: _SimpleSortedBag<Time> = []
 
@@ -26,20 +28,21 @@ public struct Sample: Equatable {
   public var count: Int { _times.count }
   public var minimum: Time? { _times.min() }
   public var maximum: Time? { _times.max() }
-  public var sum: Time { Time(_times.reduce(0.0, { $0 + $1.seconds })) }
+  public var sum: Time { Time(_times.reduce(Duration.zero, { $0 + $1.duration })) }
   public var sumSquared: Double { _times.reduce(0.0, { $0 + $1.seconds * $1.seconds })}
   
   public var mean: Time? {
     guard _times.count > 0 else { return nil }
-    return Time(sum.seconds / Double(_times.count))
+    return Time(sum.duration / _times.count)
   }
   
   public var standardDeviation: Time? {
     guard _times.count >= 2 else { return nil }
+    // FIXME: Redo this using fixed-point arithmetic
     let c = Double(_times.count)
     let sum = self.sum.seconds
     let s2: Double = (c * self.sumSquared - sum * sum) / (c * (c - 1))
-    return Time(s2.magnitude.squareRoot())
+    return .seconds(s2.magnitude.squareRoot())
   }
   
   public mutating func add(_ time: Time) {
diff --git a/Sources/CollectionsBenchmark/Basics/Size.swift b/Sources/CollectionsBenchmark/Basics/Size.swift
index 2745e6e..499ef1d 100644
--- a/Sources/CollectionsBenchmark/Basics/Size.swift
+++ b/Sources/CollectionsBenchmark/Basics/Size.swift
@@ -2,16 +2,17 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
+import Foundation // For String(format:)
 import ArgumentParser
 
-public struct Size: RawRepresentable {
+public struct Size: Sendable, RawRepresentable {
   public typealias RawValue = Int
   
   public let rawValue: RawValue
diff --git a/Sources/CollectionsBenchmark/Basics/TaskResults.swift b/Sources/CollectionsBenchmark/Basics/TaskResults.swift
index 1a2c4fe..d0ff088 100644
--- a/Sources/CollectionsBenchmark/Basics/TaskResults.swift
+++ b/Sources/CollectionsBenchmark/Basics/TaskResults.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,7 +13,7 @@ import Foundation // URL
 
 /// A series of samples taken at for various sizes for a particular
 /// benchmark task.
-public struct TaskResults {
+public struct TaskResults: Sendable {
   public typealias Element = (size: Size, sample: Sample)
 
   internal typealias _Results = _SimpleSortedDictionary<Size, Sample>
diff --git a/Sources/CollectionsBenchmark/Basics/Tick.swift b/Sources/CollectionsBenchmark/Basics/Tick.swift
index 1f8b203..f0ddfdf 100644
--- a/Sources/CollectionsBenchmark/Basics/Tick.swift
+++ b/Sources/CollectionsBenchmark/Basics/Tick.swift
@@ -2,71 +2,31 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
-#if !USE_FOUNDATION_DATE && (os(macOS) || os(iOS) || os(watchOS) || os(tvOS))
-import Foundation // For the side effect of reexporting Darwin/Glibc
+public struct Tick: Sendable {
+  typealias Clock = SuspendingClock
 
-public struct Tick {
-  internal let _value: timespec
+  internal let _value: SuspendingClock.Instant
 
-  internal init(_value: timespec) {
+  internal init(_value: SuspendingClock.Instant) {
     self._value = _value
   }
 
   public static var now: Tick {
-    guard #available(macOS 10.12, iOS 10.0, tvOS 10.0, watchOS 3.0, *) else {
-      fatalError("Please enable USE_FOUNDATION_DATE")
-    }
-    var now = timespec()
-    let r = clock_gettime(CLOCK_MONOTONIC_RAW, &now)
-    precondition(r == 0, "clock_gettime failure")
-    return Tick(_value: now)
+    Tick(_value: SuspendingClock.now)
   }
   
   public static var resolution: Time {
-    guard #available(macOS 10.12, iOS 10.0, tvOS 10.0, watchOS 3.0, *) else {
-      fatalError("Please enable USE_FOUNDATION_DATE")
-    }
-    var res = timespec()
-    let r = clock_getres(CLOCK_MONOTONIC_RAW, &res)
-    precondition(r == 0, "clock_getres failure")
-    return Tick(_value: res).elapsedTime(since: Tick(_value: timespec(tv_sec: 0, tv_nsec: 0)))
+    Time(Clock().minimumResolution)
   }
 
   public func elapsedTime(since start: Tick) -> Time {
-    let s = Double(_value.tv_sec - start._value.tv_sec)
-    let ns = Double(_value.tv_nsec - start._value.tv_nsec)
-    return Time(s + ns / 1e9)
+    Time(start._value.duration(to: self._value))
   }
 }
-
-#else
-
-import Foundation
-
-public struct Tick {
-  internal let _value: Date
-
-  internal init(_value: Date) {
-    self._value = _value
-  }
-
-  public static var now: Tick {
-    Tick(_value: Date())
-  }
-
-  public func elapsedTime(since start: Tick) -> Time {
-    Time(Double(_value.timeIntervalSince(start._value)))
-  }
-  
-  public static var resolution: Time {
-    .nanosecond
-  }
-}
-#endif
diff --git a/Sources/CollectionsBenchmark/Basics/Time.swift b/Sources/CollectionsBenchmark/Basics/Time.swift
index 52701a5..eaa02d9 100644
--- a/Sources/CollectionsBenchmark/Basics/Time.swift
+++ b/Sources/CollectionsBenchmark/Basics/Time.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -12,68 +12,77 @@
 import Foundation
 import ArgumentParser
 
-public struct Time {
-  public let seconds: TimeInterval
-  
-  public init(_ seconds: TimeInterval) {
-    precondition(!seconds.isNaN)
-    self.seconds = seconds
+public struct Time: Sendable {
+  public let duration: Duration
+
+  public init(_ duration: Duration) {
+    self.duration = duration
   }
 }
 
 extension Time {
-  public static let second = Time(1)
-  public static let millisecond = Time(1e-3)
-  public static let microsecond = Time(1e-6)
-  public static let nanosecond = Time(1e-9)
-  public static let picosecond = Time(1e-12)
-  public static let femtosecond = Time(1e-15)
-  public static let attosecond = Time(1e-18)
-  public static let zero = Time(0)
+  public static let second = Time(.seconds(1))
+  public static let millisecond = Time(.milliseconds(1))
+  public static let microsecond = Time(.microseconds(1))
+  public static let nanosecond = Time(.nanoseconds(1))
+  public static let picosecond = Time(.init(_attoseconds: 1_000_000))
+  public static let femtosecond = Time(.init(_attoseconds: 1_000))
+  public static let attosecond = Time(.init(_attoseconds: 1))
+  public static let zero = Time(.zero)
 }
 
 extension Time {
   public static func since(_ start: Tick) -> Time {
     Tick.now.elapsedTime(since: start)
   }
+
+  public static var eternity: Time { Time(Duration(_high: .max, low: .max)) }
+
+  public static func seconds(_ seconds: Double) -> Time {
+    Time(.seconds(seconds))
+  }
+
+  public var seconds: Double {
+    duration._seconds
+  }
 }
 
 extension Time: RawRepresentable {
   public var rawValue: TimeInterval { seconds }
-  
+
   public init(rawValue: TimeInterval) {
-    self.seconds = rawValue
+    self.duration = .seconds(rawValue)
   }
 }
 
 extension Time: Equatable {
   public static func == (left: Self, right: Self) -> Bool {
-    return left.seconds == right.seconds
+    return left.duration == right.duration
   }
 }
 
 extension Time: Hashable {
   public func hash(into hasher: inout Hasher) {
-    hasher.combine(seconds)
+    hasher.combine(duration)
   }
 }
 
 extension Time: Comparable {
   public static func < (left: Self, right: Self) -> Bool {
-    return left.seconds < right.seconds
+    return left.duration < right.duration
   }
 }
 
 extension Time: CustomStringConvertible {
   public var description: String {
-    if self.seconds == 0 { return "0" }
-    if self < .attosecond { return String(format: "%.3gas", seconds * 1e18) }
+    if self.duration == .zero { return "0" }
+    if self < .attosecond { return String(format: "%.3gas", seconds) }
     if self < .picosecond { return String(format: "%.3gfs", seconds * 1e15) }
     if self < .nanosecond  { return String(format: "%.3gps", seconds * 1e12) }
     if self < .microsecond { return String(format: "%.3gns", seconds * 1e9) }
     if self < .millisecond { return String(format: "%.3gµs", seconds * 1e6) }
     if self < .second      { return String(format: "%.3gms", seconds * 1e3) }
-    if self.seconds < 1000 { return String(format: "%.3gs", seconds) }
+    if self.duration < .seconds(1000) { return String(format: "%.3gs", seconds) }
     return String(format: "%gs", seconds.rounded())
   }
   
@@ -93,11 +102,19 @@ extension Time: CustomStringConvertible {
 
 extension Time: Codable {
   public init(from decoder: Decoder) throws {
-    self.seconds = try TimeInterval(from: decoder)
+    do {
+      self.duration = try Duration(from: decoder)
+    } catch DecodingError.typeMismatch {
+      self.duration = .seconds(try TimeInterval(from: decoder))
+    }
   }
   
   public func encode(to encoder: Encoder) throws {
-    try self.seconds.encode(to: encoder)
+    do {
+      try self.duration.encode(to: encoder)
+    } catch EncodingError.invalidValue {
+      try self.seconds.encode(to: encoder)
+    }
   }
 }
 
@@ -130,18 +147,18 @@ extension Time {
       let suffix = description.suffix(from: i.lowerBound)
       guard let value = Double(number) else { return nil }
       guard let scale = Time._scaleFromSuffix[String(suffix)] else { return nil }
-      self = Time(value * scale.seconds)
+      self = .seconds(value * scale.seconds)
     }
     else {
       guard let value = Double(description) else { return nil }
-      self = Time(value)
+      self = .seconds(value)
     }
   }
 }
 
 extension Time {
   public func amortized(over size: Size) -> Time {
-    return Time(seconds / TimeInterval(size.rawValue))
+    Time(duration / size.rawValue)
   }
 }
 
diff --git a/Sources/CollectionsBenchmark/Basics/Timer.swift b/Sources/CollectionsBenchmark/Basics/Timer.swift
index 2917140..e30897e 100644
--- a/Sources/CollectionsBenchmark/Basics/Timer.swift
+++ b/Sources/CollectionsBenchmark/Basics/Timer.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -57,7 +57,7 @@ public struct Timer {
     }
     let end = Tick.now
     let elapsed = end.elapsedTime(since: start)._orIfZero(Tick.resolution)
-    return Time(elapsed.seconds / Double(iterations))
+    return Time(elapsed.duration / iterations)
   }
   
   @inline(never)
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+ChartLibrary.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+ChartLibrary.swift
index b3c334c..d684235 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+ChartLibrary.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+ChartLibrary.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -47,14 +47,8 @@ extension Benchmark.ChartLibrary {
 }
 
 extension Benchmark {
-  internal func _loadLibrary(_ path: FilePath?) throws -> ChartLibrary {
-    if let path = path {
-      return try Benchmark.ChartLibrary.load(from: path)
-    }
-    if let library = self.chartLibrary {
-      return library
-    }
-    throw Benchmark.Error("No predefined library configuration")
+  internal func _loadLibrary(_ path: FilePath) throws -> ChartLibrary {
+    try Benchmark.ChartLibrary.load(from: path)
   }
 }
 
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Error.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Error.swift
index 6f44ad8..841b5bc 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Error.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Error.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,7 +10,7 @@
 //===----------------------------------------------------------------------===//
 
 extension Benchmark {
-  public struct Error: Swift.Error, CustomStringConvertible {
+  public struct Error: Sendable, Swift.Error, CustomStringConvertible {
     public let description: String
 
     public init(_ description: String) {
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Event.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Event.swift
index 68120e6..2e47a3f 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Event.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Event.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,7 +10,7 @@
 //===----------------------------------------------------------------------===//
 
 extension Benchmark {
-  public enum Event {
+  public enum Event: Sendable {
     /// An event sent at the start of measuring a benchmark task on a particular input size.
     case startTask(task: TaskID, size: Size)
 
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Main.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Main.swift
index 9c849a8..d14ae59 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Main.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Main.swift
@@ -9,8 +9,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+@preconcurrency import Foundation // for setbuf
 import ArgumentParser
-import Foundation // for setbuf
 
 extension Benchmark {
   public func main() {
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Options.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Options.swift
index ab173a5..4711002 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+Options.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+Options.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -31,7 +31,7 @@ extension Benchmark {
     public var iterations: Int = 3
 
     /// Repeat each task for at least this number of seconds.
-    public var minimumDuration = Time(0.01)
+    public var minimumDuration: Time = .seconds(0.01)
 
     /// Stop repeating a particular task/size measurement after this amount of time has passed.
     /// (When this is a finite positive value, tasks may get run for less than `iterations` times.)
@@ -173,7 +173,7 @@ extension Benchmark.Options {
 
     @Option(name: .customLong("min-duration"),
             help: "Repeat each task for at least this number of seconds")
-    public var minimumDuration = Time(0.01)
+    public var minimumDuration: Time = .seconds(0.01)
 
     @Option(name: .customLong("max-duration"),
             help: "Stop repeating tasks if this amount of time has elapsed (default: no limit)")
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark+RunOptions.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark+RunOptions.swift
index 1810487..335c262 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark+RunOptions.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark+RunOptions.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -47,7 +47,7 @@ extension Benchmark {
           // measuring a task just because it ran into some large constant
           // overhead at tiny sizes.
           if
-            time > Time(1), // Safety threshold
+            time > Time.seconds(1), // Safety threshold
             let cutoff = options.amortizedCutoff,
             time.amortized(over: size) > cutoff
           {
diff --git a/Sources/CollectionsBenchmark/Benchmark/Benchmark.swift b/Sources/CollectionsBenchmark/Benchmark/Benchmark.swift
index 94f84b4..d8d092c 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Benchmark.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Benchmark.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,12 +15,10 @@ public struct Benchmark {
   public let title: String
   internal var _tasks: _SimpleOrderedDictionary<String, AnyTask> = [:]
   internal var _inputGenerators: [_TypeBox: (Int) -> Any] = [:]
-  private let _executionContext = _ExecutionContext.shared
-
-  public var chartLibrary: ChartLibrary? = nil
 
   public init(title: String = "") {
     self.title = title
+    _setUpExecutionCheck()
     registerInputGenerator(for: Int.self) { size in
       size
     }
@@ -58,10 +56,6 @@ public struct Benchmark {
     }
   }
 
-  internal func _markAsExecuted() {
-    _executionContext._hasExecuted = true
-  }
-
   public func allTaskNames() -> [String] {
     _tasks.map { $0.key }
   }
diff --git a/Sources/CollectionsBenchmark/Benchmark/BenchmarkResults.swift b/Sources/CollectionsBenchmark/Benchmark/BenchmarkResults.swift
index 311b4d3..0851f3f 100644
--- a/Sources/CollectionsBenchmark/Benchmark/BenchmarkResults.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/BenchmarkResults.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -14,7 +14,7 @@ import SystemPackage
 import ArgumentParser
 
 /// A value containing a set of benchmark results.
-public struct BenchmarkResults {
+public struct BenchmarkResults: Sendable {
   internal typealias _Results = _SimpleOrderedDictionary<TaskID, TaskResults>
 
   internal var _tasks: _Results = [:]
diff --git a/Sources/CollectionsBenchmark/Benchmark/Task.swift b/Sources/CollectionsBenchmark/Benchmark/Task.swift
index 8abf73d..072e5c1 100644
--- a/Sources/CollectionsBenchmark/Benchmark/Task.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/Task.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -57,7 +57,7 @@ extension Task {
     }
 
     let minDuration = options.minimumDuration
-    let maxDuration = options.maximumDuration ?? Time(.infinity)
+    let maxDuration = options.maximumDuration ?? .eternity
     let wallClockStart = Tick.now
 
     // Measure the task once to get a rough estimate for its length and to
diff --git a/Sources/CollectionsBenchmark/Benchmark/TaskID.swift b/Sources/CollectionsBenchmark/Benchmark/TaskID.swift
index 85c488b..d89c992 100644
--- a/Sources/CollectionsBenchmark/Benchmark/TaskID.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/TaskID.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -12,7 +12,7 @@
 import Foundation
 import ArgumentParser
 
-public struct TaskID: Hashable {
+public struct TaskID: Sendable, Hashable {
   public var label: String {
     didSet {
       if let error = Self._validateLabel(label) {
diff --git a/Sources/CollectionsBenchmark/Benchmark/_ExecutionContext.swift b/Sources/CollectionsBenchmark/Benchmark/_ExecutionContext.swift
index 91c1966..e5c9ded 100644
--- a/Sources/CollectionsBenchmark/Benchmark/_ExecutionContext.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/_ExecutionContext.swift
@@ -2,28 +2,38 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
-import Foundation
+import Foundation // for atexit
+import Synchronization
+
+let _hasDoneSetup: Atomic<Bool> = .init(false)
+let _hasExecuted: Atomic<Bool> = .init(false)
 
 private func _exitHandler() {
-  if !_ExecutionContext.shared._hasExecuted {
+  if !_hasExecuted.load(ordering: .acquiring) {
     fatalError("Did you forget to call Benchmark.start()?")
   }
 }
 
-internal class _ExecutionContext {
-  var _hasExecuted = false
-  
-  private init() {
+internal func _setUpExecutionCheck() {
+  let (exchanged, _) = _hasDoneSetup.compareExchange(
+    expected: false, desired: true, ordering: .acquiringAndReleasing)
+  if exchanged {
     // Check that Benchmark.start() was executed before exiting the process.
+    // FIXME: Calling convention mismatch
     atexit(_exitHandler)
   }
-  
-  static let shared: _ExecutionContext = { _ExecutionContext() }()
+}
+
+internal func _markAsExecuted() {
+  guard _hasDoneSetup.load(ordering: .acquiring) else {
+    fatalError("Internal error: _markAsExecuted called before _setUpExecutionCheck")
+  }
+  _hasExecuted.store(true, ordering: .releasing)
 }
diff --git a/Sources/CollectionsBenchmark/Benchmark/_TypeBox.swift b/Sources/CollectionsBenchmark/Benchmark/_TypeBox.swift
index 9a3144c..8c3e83b 100644
--- a/Sources/CollectionsBenchmark/Benchmark/_TypeBox.swift
+++ b/Sources/CollectionsBenchmark/Benchmark/_TypeBox.swift
@@ -2,14 +2,14 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
-internal struct _TypeBox: Hashable {
+internal struct _TypeBox: Sendable, Hashable {
   let type: Any.Type
 
   init(_ type: Any.Type) {
diff --git a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+List.swift b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+List.swift
index 5a72898..4981fb4 100644
--- a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+List.swift
+++ b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+List.swift
@@ -21,10 +21,10 @@ extension _BenchmarkCLI.Library {
     }
 
     @Option(
-      help: "Path to a library configuration file in JSON format. (default: built-in library)",
+      help: "Path to a library configuration file in JSON format.",
       completion: .file(extensions: ["json"]),
       transform: { str in FilePath(str) })
-    var library: FilePath?
+    var library: FilePath
 
     @Flag(help: "List all tasks included in the library.")
     var tasks = false
diff --git a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Render.swift b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Render.swift
index ea8413d..0ef6f69 100644
--- a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Render.swift
+++ b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Render.swift
@@ -22,10 +22,10 @@ extension _BenchmarkCLI.Library {
     }
 
     @Option(
-      help: "Path to a library configuration file in JSON format. (default: built-in library)",
+      help: "Path to a library configuration file in JSON format.",
       completion: .file(extensions: ["json"]),
       transform: { str in FilePath(str) })
-    var library: FilePath?
+    var library: FilePath
 
     @Argument(
       help: "A path to a benchmark results document.",
diff --git a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Run.swift b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Run.swift
index b93c284..e7ab9ea 100644
--- a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Run.swift
+++ b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Library+Run.swift
@@ -21,10 +21,10 @@ extension _BenchmarkCLI.Library {
     }
 
     @Option(
-      help: "Path to a library configuration file in JSON format. (default: built-in library)",
+      help: "Path to a library configuration file in JSON format.",
       completion: .file(extensions: ["json"]),
       transform: { str in FilePath(str) })
-    internal var library: FilePath?
+    internal var library: FilePath
 
     @Argument(
       help: "Output filename.",
diff --git a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Render.swift b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Render.swift
index 7b090b2..7645e35 100644
--- a/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Render.swift
+++ b/Sources/CollectionsBenchmark/BenchmarkCLI/BenchmarkCLI+Render.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -15,10 +15,12 @@ import ArgumentParser
 
 extension _BenchmarkCLI {
   internal struct Render: ParsableCommand {
-    static var configuration = CommandConfiguration(
-      commandName: "render",
-      abstract: "Generate charts from benchmark results.")
-    
+    static var configuration: CommandConfiguration {
+      CommandConfiguration(
+        commandName: "render",
+        abstract: "Generate charts from benchmark results.")
+    }
+
     @Argument(help: "Path to a benchmark results document.")
     var input: String
     
diff --git a/Sources/CollectionsBenchmark/BenchmarkCLI/_Document.swift b/Sources/CollectionsBenchmark/BenchmarkCLI/_Document.swift
index a1c1014..7deadb6 100644
--- a/Sources/CollectionsBenchmark/BenchmarkCLI/_Document.swift
+++ b/Sources/CollectionsBenchmark/BenchmarkCLI/_Document.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -32,7 +32,7 @@ internal struct _Document {
   var _isDirty: Bool
 
   /// Prevent losing data by saving the output file every handful of seconds.
-  let _savePeriod = Time(10) // FIXME Maybe replace this with a command line option
+  let _savePeriod: Time = .seconds(10) // FIXME Maybe replace this with a command line option
 
   init(
     url: URL,
diff --git a/Sources/CollectionsBenchmark/Charts/Chart+Options.swift b/Sources/CollectionsBenchmark/Charts/Chart+Options.swift
index d6d0bab..5f1266c 100644
--- a/Sources/CollectionsBenchmark/Charts/Chart+Options.swift
+++ b/Sources/CollectionsBenchmark/Charts/Chart+Options.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -72,12 +72,12 @@ extension Chart.Options {
     let range = min.seconds ... max.seconds
     if self.logarithmicTime {
       let labeler: (Int) -> String = { value in
-        Time(pow(10, Double(value))).typesetDescription
+        Time.seconds(pow(10, Double(value))).typesetDescription
       }
       return Chart.LogarithmicScale(
         displayedRange: range, isDecimal: true, labeler: labeler)
     }
-    let labeler: (Double) -> String = { value in "\(Time(value))" }
+    let labeler: (Double) -> String = { value in "\(Time.seconds(value))" }
     return Chart.LinearScale(
       displayedRange: range, isDecimal: true, labeler: labeler)
   }
diff --git a/Sources/CollectionsBenchmark/Charts/Geometry/EdgeInsets.swift b/Sources/CollectionsBenchmark/Charts/Geometry/EdgeInsets.swift
index 3407ed2..00fc9a7 100644
--- a/Sources/CollectionsBenchmark/Charts/Geometry/EdgeInsets.swift
+++ b/Sources/CollectionsBenchmark/Charts/Geometry/EdgeInsets.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,7 +11,7 @@
 
 import Foundation
 
-public struct EdgeInsets: Hashable, Codable {
+public struct EdgeInsets: Sendable, Hashable, Codable {
   public var top: Double
   public var left: Double
   public var bottom: Double
diff --git a/Sources/CollectionsBenchmark/Charts/Graphics/Color.swift b/Sources/CollectionsBenchmark/Charts/Graphics/Color.swift
index f49ef17..6943d4e 100644
--- a/Sources/CollectionsBenchmark/Charts/Graphics/Color.swift
+++ b/Sources/CollectionsBenchmark/Charts/Graphics/Color.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,7 +10,7 @@
 //===----------------------------------------------------------------------===//
 
 /// A color in sRGB color space, with an alpha channel and 8-bit components.
-public struct Color: Hashable {
+public struct Color: Sendable, Hashable {
   public var red: UInt8
   public var green: UInt8
   public var blue: UInt8
diff --git a/Sources/CollectionsBenchmark/Charts/Graphics/Font.swift b/Sources/CollectionsBenchmark/Charts/Graphics/Font.swift
index 2ac1887..397a6df 100644
--- a/Sources/CollectionsBenchmark/Charts/Graphics/Font.swift
+++ b/Sources/CollectionsBenchmark/Charts/Graphics/Font.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,7 +11,7 @@
 
 import Foundation
 
-public struct Font: Hashable, Codable, CustomStringConvertible {
+public struct Font: Sendable, Hashable, Codable, CustomStringConvertible {
   public var family: String
   public var size: Double
   public var isBold = false
diff --git a/Sources/CollectionsBenchmark/Charts/Graphics/Graphics+SVG.swift b/Sources/CollectionsBenchmark/Charts/Graphics/Graphics+SVG.swift
index ab67a9a..17d61f4 100644
--- a/Sources/CollectionsBenchmark/Charts/Graphics/Graphics+SVG.swift
+++ b/Sources/CollectionsBenchmark/Charts/Graphics/Graphics+SVG.swift
@@ -2,13 +2,15 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
 //
 //===----------------------------------------------------------------------===//
 
+import Foundation
+
 extension Color {
   func _svgString() -> String {
     var r = "#"
diff --git a/Sources/CollectionsBenchmark/Charts/Graphics/Stroke.swift b/Sources/CollectionsBenchmark/Charts/Graphics/Stroke.swift
index 9994af8..6887778 100644
--- a/Sources/CollectionsBenchmark/Charts/Graphics/Stroke.swift
+++ b/Sources/CollectionsBenchmark/Charts/Graphics/Stroke.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,18 +11,18 @@
 
 import Foundation
 
-public struct Stroke: Hashable, Codable {
-  public enum CapStyle: String, Hashable, Codable {
+public struct Stroke: Sendable, Hashable, Codable {
+  public enum CapStyle: String, Sendable, Hashable, Codable {
     case butt
     case round
     case square
   }
-  public enum JoinStyle: String, Hashable, Codable {
+  public enum JoinStyle: String, Sendable, Hashable, Codable {
     case miter
     case round
     case bevel
   }
-  public struct Dash: Hashable, Codable {
+  public struct Dash: Sendable, Hashable, Codable {
     public var style: [Double]
     public var phase: Double = 0
   }
diff --git a/Sources/CollectionsBenchmark/Charts/Graphics/Text.swift b/Sources/CollectionsBenchmark/Charts/Graphics/Text.swift
index 4a2a690..179fc5d 100644
--- a/Sources/CollectionsBenchmark/Charts/Graphics/Text.swift
+++ b/Sources/CollectionsBenchmark/Charts/Graphics/Text.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -11,8 +11,8 @@
 
 import Foundation // URL
 
-public struct Text: Codable {
-  public struct Style: Hashable, Codable {
+public struct Text: Sendable, Codable {
+  public struct Style: Sendable, Hashable, Codable {
     public var font: Font
     public var color: Color
   }
diff --git a/Sources/CollectionsBenchmark/Charts/Theme.swift b/Sources/CollectionsBenchmark/Charts/Theme.swift
index 62e7c08..e931a50 100644
--- a/Sources/CollectionsBenchmark/Charts/Theme.swift
+++ b/Sources/CollectionsBenchmark/Charts/Theme.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -13,8 +13,8 @@ import Foundation
 import SystemPackage
 import ArgumentParser
 
-public struct Theme: Codable {
-  public enum LegendPosition: String, Codable {
+public struct Theme: Sendable, Codable {
+  public enum LegendPosition: String, Sendable, Codable {
     case hidden
     case topLeft
     case topRight
@@ -64,7 +64,7 @@ public struct Theme: Codable {
 }
 
 extension Theme {
-  public struct CurveTheme: Hashable, Codable {
+  public struct CurveTheme: Sendable, Hashable, Codable {
     public var color: Color
     public var lineWidth: Double
 
@@ -129,7 +129,7 @@ extension Theme {
 }
 
 extension Theme {
-  public static var knownThemes: Dictionary<String, Theme> = [
+  public static let knownThemes: Dictionary<String, Theme> = [
     "light": Theme.light,
     "dark": Theme.dark,
   ]
diff --git a/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedDictionary.swift b/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedDictionary.swift
index 24f862c..d071a21 100644
--- a/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedDictionary.swift
+++ b/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedDictionary.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -30,6 +30,9 @@ struct _SimpleOrderedDictionary<Key: Hashable, Value> {
   }
 }
 
+extension _SimpleOrderedDictionary: Sendable
+where Key: Sendable, Value: Sendable {}
+
 extension _SimpleOrderedDictionary {
   struct _Item: Hashable {
     var key: Key
@@ -50,6 +53,9 @@ extension _SimpleOrderedDictionary {
   }
 }
 
+extension _SimpleOrderedDictionary._Item: Sendable
+where Key: Sendable, Value: Sendable {}
+
 extension _SimpleOrderedDictionary {
   func _checkInvariants() {
     for item in _elements {
diff --git a/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedSet.swift b/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedSet.swift
index 5409a85..aabd369 100644
--- a/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedSet.swift
+++ b/Sources/CollectionsBenchmark/Utilities/_SimpleOrderedSet.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -30,6 +30,8 @@ struct _SimpleOrderedSet<Element: Hashable> {
   }
 }
 
+extension _SimpleOrderedSet: Sendable where Element: Sendable {}
+
 extension _SimpleOrderedSet {
   struct _Item: Hashable {
     var value: Element
@@ -50,6 +52,8 @@ extension _SimpleOrderedSet {
   }
 }
 
+extension _SimpleOrderedSet._Item: Sendable where Element: Sendable {}
+
 extension _SimpleOrderedSet {
   func _checkInvariants() {
     precondition(_elements.count == _hashTable.count)
diff --git a/Sources/CollectionsBenchmark/Utilities/_SimpleSortedBag.swift b/Sources/CollectionsBenchmark/Utilities/_SimpleSortedBag.swift
index e0389f9..aa27a9a 100644
--- a/Sources/CollectionsBenchmark/Utilities/_SimpleSortedBag.swift
+++ b/Sources/CollectionsBenchmark/Utilities/_SimpleSortedBag.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -29,6 +29,8 @@ struct _SimpleSortedBag<Element: Comparable> {
   }
 }
 
+extension _SimpleSortedBag: Sendable where Element: Sendable {}
+
 extension _SimpleSortedBag: ExpressibleByArrayLiteral {
   init(arrayLiteral elements: Element...) {
     self.init(elements)
diff --git a/Sources/CollectionsBenchmark/Utilities/_SimpleSortedDictionary.swift b/Sources/CollectionsBenchmark/Utilities/_SimpleSortedDictionary.swift
index b884154..94115c7 100644
--- a/Sources/CollectionsBenchmark/Utilities/_SimpleSortedDictionary.swift
+++ b/Sources/CollectionsBenchmark/Utilities/_SimpleSortedDictionary.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift Collections open source project
 //
-// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -22,6 +22,9 @@ struct _SimpleSortedDictionary<Key: Comparable, Value> {
   }
 }
 
+extension _SimpleSortedDictionary: Sendable
+where Key: Sendable, Value: Sendable {}
+
 extension _SimpleSortedDictionary {
   struct _Item: Comparable {
     var key: Key
@@ -43,6 +46,9 @@ extension _SimpleSortedDictionary {
   }
 }
 
+extension _SimpleSortedDictionary._Item: Sendable
+where Key: Sendable, Value: Sendable {}
+
 extension _SimpleSortedDictionary {
   init<S: Sequence>(
     uniqueKeysWithValues elements: S
diff --git a/Tests/CollectionsBenchmarkTests/SimpleOrderedDictionaryTests.swift b/Tests/CollectionsBenchmarkTests/SimpleOrderedDictionaryTests.swift
index dad0ab7..ed4823e 100644
--- a/Tests/CollectionsBenchmarkTests/SimpleOrderedDictionaryTests.swift
+++ b/Tests/CollectionsBenchmarkTests/SimpleOrderedDictionaryTests.swift
@@ -20,7 +20,7 @@ func _expectEqual<
 >(
   _ actual: S1,
   _ expected: S2,
-  file: StaticString = #file,
+  file: StaticString = #filePath,
   line: UInt = #line
 ) where
   S1.Element == (key: A, value: B),
diff --git a/Tests/CollectionsBenchmarkTests/UtilitiesTests.swift b/Tests/CollectionsBenchmarkTests/UtilitiesTests.swift
index a47cd78..4a032f2 100644
--- a/Tests/CollectionsBenchmarkTests/UtilitiesTests.swift
+++ b/Tests/CollectionsBenchmarkTests/UtilitiesTests.swift
@@ -19,7 +19,7 @@ final class UtilitiesTests: XCTestCase {
       _ input: String,
       _ output: String,
       windows: String? = nil,
-      file: StaticString = #file,
+      file: StaticString = #filePath,
       line: UInt = #line
     ) {
       #if os(Windows)