pub fn new<S>(stream: S) -> ByteStream
    where
        S: Stream<Item = Result<Bytes, io::Error>> + Send + 'static,
    {
        ByteStream {
            size_hint: None,
            inner: Box::pin(stream),
        }
    }
Create a new `ByteStream` by wrapping a `futures` stream.
rusoto/signature/src/stream.rs