Extensions

Extensions

Extensions return ITaskScheduler decorators. They do not own or dispose the scheduler or flow they wrap. Keep the underlying ITaskFlow reference and dispose it at the owner boundary.

Extension	Package and frameworks	Effect	Details
CreateCancelPrevious	TaskFlow; all targets	Cancels older unfinished submissions	Cancellation
CreateCancellationScope	TaskFlow; all targets	Links a shared lifetime token	Cancellation
WithTimeout	TaskFlow; all targets	Adds a queue-and-execution timeout	Reliability
WithThrottle	TaskFlow on .NET 8/10; TaskFlow.Extensions.Time on netstandard2.0	Rejects submissions inside an admission interval	Reliability
OnError	TaskFlow; all targets	Observes matching failures and rethrows	Reliability
WithOperationName	TaskFlow; all targets	Adds an operation-name annotation	Observability
Intercept	TaskFlow; all targets	Runs synchronous or asynchronous lifecycle callbacks	Observability
WithLogging	TaskFlow.Microsoft.Extensions.Logging; all targets	Emits structured lifecycle events	Observability

Composition

Decorator order is observable. The last extension call produces the outermost scheduler and sees a submission first.

await using var flow = new TaskFlow();

ITaskScheduler operations = flow
    .WithLogging(logger)
    .WithTimeout(TimeSpan.FromSeconds(10))
    .CreateCancellationScope(lifetimeToken)
    .WithOperationName("orders.persist");

await operations.Enqueue(token => PersistAsync(token));

Here the operation-name annotation travels inward to timeout and logging. The caller token, lifetime token, timeout signal, and flow-disposal token can all request cancellation. The delegate must cooperate with the token it receives.

static Task PersistAsync(CancellationToken token) => Task.CompletedTask;

Common rules

• Await or return an operation task when its outcome matters to the caller. For intentional fire-and-forget work, discard it explicitly and add failure reporting inside the operation or through a decorator when needed.
• Dispose the underlying flow, not its decorators.
• Treat cancellation as a request rather than proof that work stopped.
• Use named local functions for value-returning asynchronous delegates if overload resolution is ambiguous.
• Test policy ordering because moving one decorator can change which annotations or failures another decorator observes.