Given:
Stream<String> stream = new Stream<String>.fromIterable(['mene', 'mene', 'tekel', 'parsin']);
then:
print('BEFORE');
stream.listen((s) { print(s); });
print('AFTER');
yields:
BEFORE
AFTER
mene
mene
tekel
parsin
whereas:
print('BEFORE');
await for(String s in stream) { print(s); }
print('AFTER');
yields:
BEFORE
mene
mene
tekel
parsin
AFTER
stream.listen() sets up code that will be put on the event queue when an event arrives, then following code is executed.
await for suspends between events and keeps doing so until the stream is done, so code following it will not be executed until that happens.
I use `await for when I have a stream that I know will have finite events, and I need to process them before doing anything else (essentially as if I’m dealing with a list of futures).
Check https://www.dartlang.org/articles/language/beyond-async for a description of await for.