stream: add `next` and `map` utility fn (#1962)

Introduces `StreamExt` trait. This trait will be used to add utility functions
to make working with streams easier. This patch includes two functions:

* `next`: a future returning the item in the stream.
* `map`: transform each item in the stream.

1 files changed, 4 insertions, 0 deletions

diff --git a/tokio/src/lib.rs b/tokio/src/lib.rs
index 66fd7975..831a5241 100644
--- a/tokio/src/lib.rs
+++ b/tokio/src/lib.rs
@@ -241,6 +241,10 @@ cfg_signal! {
     pub mod signal;
 }
 
+cfg_stream! {
+    pub mod stream;
+}
+
 cfg_sync! {
     pub mod sync;
 }