Dispatcher
Abstraction over the four standard dispatchers, meant to be injected into classes instead of hardcoding Dispatchers.* so tests can swap in a test dispatcher with virtual time.
Example:
class UserRepository(private val dispatchers: DispatcherProvider = DefaultDispatcherProvider) {
suspend fun load() = withContext(dispatchers.io) { api.fetch() }
}
// In a test:
val repo = UserRepository(DispatcherProvider.of(StandardTestDispatcher(testScheduler)))Rules: DISPATCH_005 (inject dispatchers for testability), KMP_001 (no Dispatchers.IO in commonMain; see ioCompat), TEST_005 (no hardcoded dispatcher in a class). See docs/BEST_PRACTICES_COROUTINES.md sections 3.5, 11.1 and 6.5.
Requires opting in to ExperimentalStructuredCoroutines. Any provider can be wrapped by traced (event tracing) or instrumented (basic diagnostics).
See also
Inheritors
Properties
Dispatcher for CPU-bound work.
Dispatcher for blocking IO. The default implementation resolves it through ioCompat.
UI dispatcher. May be unavailable on platforms without a main dispatcher (for example a plain JVM process without a UI toolkit); in that case accessing it fails the way Dispatchers.Main does.
Unconfined dispatcher. Runs in the caller thread until the first suspension; avoid for work that needs thread affinity.
Functions
Wraps this provider's main, io and default dispatchers in InstrumentedDispatchers with those labels; unconfined is returned as is (see InstrumentedDispatcherProvider). Wrapping is lazy: nothing (including Dispatchers.Main) is read until the corresponding property is accessed.
Wraps this provider's main, io and default dispatchers in TracingDispatchers labeled "main", "io" and "default" that report to sink. unconfined is returned as is.