This impl had a bound on `StreamReader<S, E>`; this is incorrect
because:
- The second generic parameter to `StreamReader` is not an error type;
it's a buffer type.
- The `Stream` error type in `StreamReader` should not need to be the
same as the `Sink` error type.
This "passthrough" `Sink` impl was effectively unusable because it
required the `Sink` error type be the same as the `StreamReader` buffer
type.
Resolve this by allowing the `StreamReader` buffer to be anything in
this impl.
This change removes all references to `Stream` from
within the `tokio` crate and moves them into a new
`tokio-stream` crate. Most types have had their
`impl Stream` removed as well in-favor of their
inherent methods.
Closes#2870
These functions have object safety issues. It also has been decided to
avoid vectored operations on the I/O traits. A later PR will bring back
vectored operations on specific types that support them.
Refs: #2879, #2716
Josh Triplett