next method
Implementation
Future<List<int>> next() {
if (_npack == 0) {
if (done) {
return Future<List<int>>.error("stream closed");
}
_nfut += 1;
_queue.addLast(Completer<List<int>>());
return _queue.last.future;
} else {
Completer<List<int>> c = _queue.removeFirst();
_npack -= 1;
return c.future;
}
}