forEach method

Future forEach (void action(T element))

Executes action on each element of the stream.

Completes the returned Future when all elements of the stream have been processed.

If the stream contains an error, or if the call to action throws, the returned future completes with that error, and processing stops.

Implementation 

Future forEach(void action(T element)) {
  _Future future = new _Future();
  StreamSubscription subscription;
  subscription = this.listen(
      (T element) {
        // TODO(floitsch): the type should be 'void' and inferred.
        _runUserCode<dynamic>(() => action(element), (_) {},
            _cancelAndErrorClosure(subscription, future));
      },
      onError: future._completeError,
      onDone: () {
        future._complete(null);
      },
      cancelOnError: true);
  return future;
}