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, 2 deletions

diff --git a/tokio-util/tests/udp.rs b/tokio-util/tests/udp.rs
index af8002bd..51c65c63 100644
--- a/tokio-util/tests/udp.rs
+++ b/tokio-util/tests/udp.rs
@@ -1,4 +1,4 @@
-use tokio::net::UdpSocket;
+use tokio::{net::UdpSocket, stream::StreamExt};
 use tokio_util::codec::{Decoder, Encoder};
 use tokio_util::udp::UdpFramed;
 
@@ -6,7 +6,6 @@ use bytes::{BufMut, BytesMut};
 use futures::future::try_join;
 use futures::future::FutureExt;
 use futures::sink::SinkExt;
-use futures::stream::StreamExt;
 use std::io;
 
 #[tokio::test]