changed timesource to use clock

revert var

Author: akbashev

Tests/DistributedClusterTests/Cluster/SWIM/SWIMActorClusteredTests.swift

@@ -484,18 +484,21 @@ final class SWIMActorClusteredTests: ClusteredActorSystemsXCTestCase {
 }
 
 class TestTimeSource {
-    let currentTime: UnsafeAtomic<UInt64>
+    private var instant: ContinuousClock.Instant
 
-    /// starting from 1 to ensure .distantPast is already expired
-    init(currentTime: UInt64 = 1) {
-        self.currentTime = .create(currentTime)
+    /// starting from a value close to the distant past
+    init(currentTime: ContinuousClock.Instant = (.now - .nanoseconds(1))) {
+        self.instant = currentTime
     }
 
-    func now() -> DispatchTime {
-        DispatchTime(uptimeNanoseconds: self.currentTime.load(ordering: .relaxed))
+    /// Returns the current mocked time as ContinuousClock.Instant
+    @Sendable
+    func now() -> ContinuousClock.Instant {
+        self.instant
     }
 
-    func tick() {
-        _ = self.currentTime.loadThenWrappingIncrement(by: 100, ordering: .relaxed)
+    /// Advances the mocked time by the specified duration (default 100 nanoseconds, for compatibility)
+    func tick(by duration: Duration = .nanoseconds(100)) {
+        self.instant += duration
     }
 }