io: driver internal cleanup (#3124)

* Removes duplicated code by moving it to `Registration`.
* impl `Deref` for `PollEvented` to avoid `get_ref()`.
* Avoid extra waker clones in I/O driver.
* Add `Interest` wrapper around `mio::Interest`.

1 files changed, 1 insertions, 2 deletions

diff --git a/tokio/src/io/mod.rs b/tokio/src/io/mod.rs
index 20d92233..499633ee 100644
--- a/tokio/src/io/mod.rs
+++ b/tokio/src/io/mod.rs
@@ -206,8 +206,7 @@ pub use std::io::{Error, ErrorKind, Result, SeekFrom};
 
 cfg_io_driver! {
     pub(crate) mod driver;
-
-    mod registration;
+    pub(crate) use driver::Interest;
 
     mod poll_evented;