contains method

@override AsObservableFuture<bool> contains (Object needle)

Returns whether needle occurs in the elements provided by this stream.

Compares each element of this stream to needle using Object.==. If an equal element is found, the returned future is completed with true. If this stream ends without finding a match, the future is completed with false.

If this stream emits an error, or the call to Object.== throws, the returned future is completed with that error, and processing stops.

Implementation

@override
AsObservableFuture<bool> contains(Object needle) =>
    AsObservableFuture<bool>(_stream.contains(needle));