add stream::join

Signed-off-by: Yoshua Wuyts <yoshuawuyts@gmail.com>

Cargo.toml

@@ -25,6 +25,7 @@ docs = []
 unstable = []
 
 [dependencies]
+async-macros = "1.0.0"
 async-task = "1.0.0"
 cfg-if = "0.1.9"
 crossbeam-channel = "0.3.9"

src/stream/mod.rs

@@ -42,5 +42,9 @@ cfg_if! {
         pub use double_ended_stream::DoubleEndedStream;
         pub use from_stream::FromStream;
         pub use into_stream::IntoStream;
+
+        #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
+        #[doc(inline)]
+        pub use async_macros::{join_stream as join, JoinStream as Join};
     }
 }