refactor(lib): importing Unpin is not needed in 2021 edition

src/common/io/rewind.rs

@@ -1,4 +1,3 @@
-use std::marker::Unpin;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::{cmp, io};

src/proto/h1/io.rs

@@ -3,7 +3,6 @@ use std::fmt;
 #[cfg(feature = "server")]
 use std::future::Future;
 use std::io::{self, IoSlice};
-use std::marker::Unpin;
 use std::mem::MaybeUninit;
 use std::pin::Pin;
 use std::task::{Context, Poll};

src/proto/h2/server.rs

@@ -1,6 +1,5 @@
 use std::error::Error as StdError;
 use std::future::Future;
-use std::marker::Unpin;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::time::Duration;

src/server/conn/http1.rs

@@ -3,7 +3,6 @@
 use std::error::Error as StdError;
 use std::fmt;
 use std::future::Future;
-use std::marker::Unpin;
 use std::pin::Pin;
 use std::sync::Arc;
 use std::task::{Context, Poll};

src/server/conn/http2.rs

@@ -3,7 +3,6 @@
 use std::error::Error as StdError;
 use std::fmt;
 use std::future::Future;
-use std::marker::Unpin;
 use std::pin::Pin;
 use std::sync::Arc;
 use std::task::{Context, Poll};

src/upgrade.rs

@@ -44,7 +44,6 @@ use std::error::Error as StdError;
 use std::fmt;
 use std::future::Future;
 use std::io;
-use std::marker::Unpin;
 use std::pin::Pin;
 use std::sync::{Arc, Mutex};
 use std::task::{Context, Poll};