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, 1 insertions, 1 deletions

diff --git a/tokio/tests/io_lines.rs b/tokio/tests/io_lines.rs
index 3775cae0..2f6b3393 100644
--- a/tokio/tests/io_lines.rs
+++ b/tokio/tests/io_lines.rs
@@ -20,7 +20,7 @@ async fn lines_inherent() {
 
 #[tokio::test]
 async fn lines_stream() {
-    use futures::StreamExt;
+    use tokio::stream::StreamExt;
 
     let rd: &[u8] = b"hello\r\nworld\n\n";
     let mut st = rd.lines();