style(server): remove FutureExt::boxed to unify project style

src/server/tcp.rs

@@ -4,7 +4,6 @@ use std::net::{SocketAddr, TcpListener as StdTcpListener};
 use std::time::Duration;
 
 use futures_core::Stream;
-use futures_util::FutureExt as _;
 use tokio_net::driver::Handle;
 use tokio_net::tcp::TcpListener;
 use tokio_timer::Delay;
@@ -106,10 +105,9 @@ impl AddrIncoming {
         }
         self.timeout = None;
 
-        let mut accept_fut = self.listener.accept().boxed();
-
+        let mut accept = self.listener.accept();
         loop {
-            match accept_fut.poll_unpin(cx) {
+            match unsafe { Pin::new_unchecked(&mut accept) }.poll(cx) {
                 Poll::Ready(Ok((socket, addr))) => {
                     if let Some(dur) = self.tcp_keepalive_timeout {
                         if let Err(e) = socket.set_keepalive(Some(dur)) {