Join (and other stream types) should implement Stream

[zeenix]

I was very surprised when I tried to call poll_next on Pin<&mut Join> and compiler told me there is no such method. Seems like an oversight?

[danieldg]

The primary reason why the adapters don't impl futures::Stream: if they did, then if both the OrderedStreamExt and FuturesExt traits were in scope, the call join.next() would be ambiguous. This is particularly important for adapters like map. In addition, the choice of exactly what to return from the stream might be ambiguous (that's why into_stream and into_tuple_stream both exist).

[zeenix]

The primary reason why the adapters don't impl futures::Stream: if they did, then if both the OrderedStreamExt and FuturesExt traits were in scope, the call join.next() would be ambiguous.

There is an easy around around that but if this crate wanted to avoid this, OrderedStreamExt::next should have been named differently then.

that's why into_stream and into_tuple_stream both exist).

I guess that's good enough.