Nonsending Clocks

Sources/Clocks/ImmediateClock.swift

@@ -133,18 +133,17 @@
       }
     }
 
-    public private(set) var now: Instant
+    public internal(set) var now: Instant
     public private(set) var minimumResolution: Duration = .zero
-    private let lock = NSLock()
+    let lock = NSLock()
 
     public init(now: Instant = .init()) {
       self.now = now
     }
 
-    public func sleep(until deadline: Instant, tolerance: Duration?) async throws {
+    public func sleep(until deadline: Instant, tolerance: Duration?) throws {
       try Task.checkCancellation()
       self.lock.sync { self.now = deadline }
-      await Task.megaYield()
     }
   }
 

Sources/Clocks/NonsendingClock.swift

@@ -0,0 +1,34 @@
+#if compiler(>=6.2)
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  public protocol NonsendingClock<Duration>: Clock {
+    nonisolated(nonsending)
+      func sleep(until deadline: Instant, tolerance: Instant.Duration?) async throws
+  }
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension NonsendingClock {
+    nonisolated(nonsending)
+      public func sleep(for duration: Duration, tolerance: Instant.Duration? = nil) async throws
+    {
+      try await sleep(until: now.advanced(by: duration), tolerance: tolerance)
+    }
+  }
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension AnyClock: NonsendingClock {}
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension ContinuousClock: NonsendingClock {}
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension ImmediateClock: NonsendingClock {}
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension SuspendingClock: NonsendingClock {}
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension TestClock: NonsendingClock {}
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  extension UnimplementedClock: NonsendingClock {}
+#endif