Method Timeout

Timeout<TSource>(IAsyncEnumerable<TSource>, TimeSpan)

Applies a timeout policy for each element in the async-enumerable sequence. If the next element isn't received within the specified timeout duration, a TimeoutException is propagated to the consumer.

Declaration

public static IAsyncEnumerable<TSource> Timeout<TSource>(this IAsyncEnumerable<TSource> source, TimeSpan timeout)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	Source sequence to perform a timeout for.
TimeSpan	timeout	Maximum duration between values before a timeout occurs.

Returns

Type	Description
IAsyncEnumerable<TSource>	The source sequence with a TimeoutException in case of a timeout.

Type Parameters

Name	Description
TSource	The type of the elements in the source sequence.

Remarks

Specifying a Zero value for timeout is not recommended but supported, causing timeout timers to be scheduled that are due immediately. However, this doesn't guarantee a timeout will occur. If the iteration is synchronous, then the timeout will not be evaluated at all. Additionally, even a Zero timeout has a minimum time to be handled, and the action to propagate a timeout may not execute immediately. In such cases, the next element may arrive before the scheduler gets a chance to run the timeout action.

Note: If source is completely synchronous, then the timeout will not be evaluated at all. If the iteration is synchronous and takes longer than timeout, no exception will be thrown.

This operator does not throw immediately on the expiration of timeout. It is a violation of spec to attempt to dispose or otherwise interact with an IAsyncEnumerator<T> while the MoveNextAsync() task is not completed. The CancellationToken provided to the inner enumerable will be canceled when the timeout is expired, but this operator will continue to wait until the task is complete or canceled before throwing a TimeoutException.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	timeout is less than Zero.
TimeoutException	If no element is produced within timeout from the previous element.