Materializes to Task< TResult> that completes on getting termination message. The task completes with success when received complete message from upstream or cancel from downstream. It fails with the same error when received error message from downstream. It is recommended to use the internally optimized Left< TLeft, TRight> (TLeft, TRight) and Right< TLeft, TRight> (TLeft, TRight) combiners where appropriate instead of manually writing functions that pass through one of the values.

public static Flow<TIn, TOut, TMat2> WatchTermination<TIn, TOut, TMat, TMat2>(
	this Flow<TIn, TOut, TMat> flow,
	Func<TMat, Task, TMat2> materializerFunction
)
where TIn : TOut

[<ExtensionAttribute>]
static member WatchTermination : 
        flow : Flow<'TIn, 'TOut, 'TMat> * 
        materializerFunction : Func<'TMat, Task, 'TMat2> -> Flow<'TIn, 'TOut, 'TMat2>  when 'TIn : 'TOut