refactor(lib): fix many lint warnings

src/client/conn.rs

@@ -8,7 +8,6 @@
 //! If don't have need to manage connections yourself, consider using the
 //! higher-level [Client](super) API.
 use std::fmt;
-use std::marker::PhantomData;
 use std::mem;
 use std::sync::Arc;
 

src/client/connect/dns.rs

@@ -14,10 +14,8 @@ use std::net::{
     SocketAddrV4, SocketAddrV6,
 };
 use std::str::FromStr;
-use std::sync::Arc;
 
 use futures_util::{FutureExt, StreamExt};
-use tokio_executor::TypedExecutor;
 use tokio_sync::{mpsc, oneshot};
 
 use crate::common::{Future, Never, Pin, Poll, Unpin, task};
@@ -330,7 +328,7 @@ impl Resolve for TokioThreadpoolGaiResolver {
 impl Future for TokioThreadpoolGaiFuture {
     type Output = Result<GaiAddrs, io::Error>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, _cx: &mut task::Context<'_>) -> Poll<Self::Output> {
         match ready!(tokio_executor::threadpool::blocking(|| (self.name.as_str(), 0).to_socket_addrs())) {
             Ok(Ok(iter)) => Poll::Ready(Ok(GaiAddrs { inner: IpAddrs { iter } })),
             Ok(Err(e)) => Poll::Ready(Err(e)),

src/client/dispatch.rs

@@ -2,7 +2,7 @@ use futures_core::Stream;
 use futures_channel::{mpsc, oneshot};
 use futures_util::future;
 
-use crate::common::{Future, Never, Pin, Poll, task};
+use crate::common::{Future, Pin, Poll, task};
 
 pub type RetryPromise<T, U> = oneshot::Receiver<Result<U, (crate::Error, Option<T>)>>;
 pub type Promise<T> = oneshot::Receiver<Result<T, crate::Error>>;
@@ -136,9 +136,6 @@ pub struct Receiver<T, U> {
     taker: want::Taker,
 }
 
-//impl<T, U> Stream for Receiver<T, U> {
-//    type Item = (T, Callback<T, U>);
-
 impl<T, U> Receiver<T, U> {
     pub(crate) fn poll_next(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<(T, Callback<T, U>)>> {
         match Pin::new(&mut self.inner).poll_next(cx) {