Update to tokio 1.1 (#2172)

## Issue Addressed

resolves #2129
resolves #2099 
addresses some of #1712
unblocks #2076
unblocks #2153 

## Proposed Changes

- Updates all the dependencies mentioned in #2129, except for web3. They haven't merged their tokio 1.0 update because they are waiting on some dependencies of their own. Since we only use web3 in tests, I think updating it in a separate issue is fine. If they are able to merge soon though, I can update in this PR. 

- Updates `tokio_util` to 0.6.2 and `bytes` to 1.0.1.

- We haven't made a discv5 release since merging tokio 1.0 updates so I'm using a commit rather than release atm. **Edit:** I think we should merge an update of `tokio_util` to 0.6.2 into discv5 before this release because it has panic fixes in `DelayQueue`  --> PR in discv5:  https://github.com/sigp/discv5/pull/58

## Additional Info

tokio 1.0 changes that required some changes in lighthouse:

- `interval.next().await.is_some()` -> `interval.tick().await`
- `sleep` future is now `!Unpin` -> https://github.com/tokio-rs/tokio/issues/3028
- `try_recv` has been temporarily removed from `mpsc` -> https://github.com/tokio-rs/tokio/issues/3350
- stream features have moved to `tokio-stream` and `broadcast::Receiver::into_stream()` has been temporarily removed -> `https://github.com/tokio-rs/tokio/issues/2870
- I've copied over the `BroadcastStream` wrapper from this PR, but can update to use `tokio-stream` once it's merged https://github.com/tokio-rs/tokio/pull/3384

Co-authored-by: realbigsean <seananderson33@gmail.com>

beacon_node/eth2_libp2p/src/rpc/handler.rs

@@ -7,6 +7,7 @@ use super::{RPCReceived, RPCSend};
 use crate::rpc::protocol::{InboundFramed, OutboundFramed};
 use fnv::FnvHashMap;
 use futures::prelude::*;
+use futures::{Sink, SinkExt};
 use libp2p::core::upgrade::{
     InboundUpgrade, NegotiationError, OutboundUpgrade, ProtocolError, UpgradeError,
 };
@@ -133,7 +134,7 @@ enum HandlerState {
     ///
     /// While in this state the handler rejects new requests but tries to finish existing ones.
     /// Once the timer expires, all messages are killed.
-    ShuttingDown(Sleep),
+    ShuttingDown(Box<Sleep>),
     /// The handler is deactivated. A goodbye has been sent and no more messages are sent or
     /// received.
     Deactivated,
@@ -239,9 +240,9 @@ where
                 self.dial_queue.push((id, req));
             }
 
-            self.state = HandlerState::ShuttingDown(sleep_until(
+            self.state = HandlerState::ShuttingDown(Box::new(sleep_until(
                 TInstant::now() + Duration::from_secs(SHUTDOWN_TIMEOUT_SECS as u64),
-            ));
+            )));
         }
     }
 

beacon_node/eth2_libp2p/src/rpc/protocol.rs

@@ -9,8 +9,8 @@ use crate::rpc::{
     MaxRequestBlocks, MAX_REQUEST_BLOCKS,
 };
 use futures::future::BoxFuture;
-use futures::prelude::*;
 use futures::prelude::{AsyncRead, AsyncWrite};
+use futures::{FutureExt, SinkExt, StreamExt};
 use libp2p::core::{InboundUpgrade, OutboundUpgrade, ProtocolName, UpgradeInfo};
 use ssz::Encode;
 use ssz_types::VariableList;
@@ -278,7 +278,7 @@ impl ProtocolName for ProtocolId {
 
 pub type InboundOutput<TSocket, TSpec> = (RPCRequest<TSpec>, InboundFramed<TSocket, TSpec>);
 pub type InboundFramed<TSocket, TSpec> =
-    Framed<TimeoutStream<Compat<TSocket>>, InboundCodec<TSpec>>;
+    Framed<std::pin::Pin<Box<TimeoutStream<Compat<TSocket>>>>, InboundCodec<TSpec>>;
 
 impl<TSocket, TSpec> InboundUpgrade<TSocket> for RPCProtocol<TSpec>
 where
@@ -304,7 +304,7 @@ where
             let mut timed_socket = TimeoutStream::new(socket);
             timed_socket.set_read_timeout(Some(Duration::from_secs(TTFB_TIMEOUT)));
 
-            let socket = Framed::new(timed_socket, codec);
+            let socket = Framed::new(Box::pin(timed_socket), codec);
 
             // MetaData requests should be empty, return the stream
             match protocol_name {

beacon_node/eth2_libp2p/src/rpc/rate_limiter.rs

@@ -1,6 +1,5 @@
 use crate::rpc::{Protocol, RPCRequest};
 use fnv::FnvHashMap;
-use futures::StreamExt;
 use libp2p::PeerId;
 use std::convert::TryInto;
 use std::future::Future;
@@ -241,7 +240,7 @@ impl Future for RPCRateLimiter {
     type Output = ();
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        while let Poll::Ready(Some(_)) = self.prune_interval.poll_next_unpin(cx) {
+        while let Poll::Ready(_) = self.prune_interval.poll_tick(cx) {
             self.prune();
         }