Impl newtype StreamReadable

It wraps a `Stream<Item = Result<Bytes, E>>` and implements `Read` and
`BufRead` on it so that it can be used on sync context.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

src/helpers.rs

@@ -22,6 +22,7 @@ mod ui_thread;
 pub use ui_thread::UIThread;
 
 mod extracter;
+mod stream_readable;
 
 mod readable_rx;