stream: move the adapter types to an inline mod

Created an inline adapters mod that contains the adapter types, to
keep the tokio_stream interface organized.

Fixes: #6656

tokio-stream/src/lib.rs

@@ -81,10 +81,15 @@ pub mod wrappers;
 
 mod stream_ext;
 pub use stream_ext::{collect::FromStream, StreamExt};
-pub use stream_ext::{
-    AllFuture, AnyFuture, Chain, Filter, FilterMap, FoldFuture, Fuse, Map, MapWhile, Merge, Next,
-    Peekable, Skip, SkipWhile, Take, TakeWhile, Then, TryNext,
-};
+/// Adapters for types that implement the `Stream` trait.
+/// Created through the tokio [`StreamExt`](crate::stream_ext::StreamExt) methods.
+pub mod adapters {
+    pub use crate::stream_ext::{
+        AllFuture, AnyFuture, Chain, Filter, FilterMap, FoldFuture, Fuse, Map, MapWhile, Merge,
+        Next, Peekable, Skip, SkipWhile, Take, TakeWhile, Then, TryNext,
+    };
+}
+
 cfg_time! {
     pub use stream_ext::timeout::{Elapsed, Timeout};
 }

tokio-stream/tests/stream_chain.rs

@@ -1,11 +1,12 @@
-use tokio_stream::{self as stream, Chain, Stream, StreamExt};
+use tokio_stream::{self as stream, Stream, StreamExt};
 use tokio_test::{assert_pending, assert_ready, task};
 
 mod support {
     pub(crate) mod mpsc;
 }
 
 use support::mpsc;
+use tokio_stream::adapters::Chain;
 
 #[tokio::test]
 async fn basic_usage() {