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/network/Cargo.toml

@@ -30,12 +30,13 @@ eth2_ssz_types = { path =  "../../consensus/ssz_types" }
 tree_hash = "0.1.1"
 futures = "0.3.7"
 error-chain = "0.12.4"
-tokio = { version = "0.3.2", features = ["full"] }
+tokio = { version = "1.1.0", features = ["full"] }
+tokio-stream = "0.1.2"
 parking_lot = "0.11.0"
 smallvec = "1.6.1"
 rand = "0.7.3"
 fnv = "1.0.7"
-rlp = "0.4.6"
+rlp = "0.5.0"
 lazy_static = "1.4.0"
 lighthouse_metrics = { path = "../../common/lighthouse_metrics" }
 task_executor = { path = "../../common/task_executor" }

beacon_node/network/src/persisted_dht.rs

@@ -38,7 +38,7 @@ impl StoreItem for PersistedDht {
     }
 
     fn as_store_bytes(&self) -> Vec<u8> {
-        rlp::encode_list(&self.enrs)
+        rlp::encode_list(&self.enrs).to_vec()
     }
 
     fn from_store_bytes(bytes: &[u8]) -> Result<Self, StoreError> {

beacon_node/network/src/router/mod.rs

@@ -19,6 +19,7 @@ use processor::Processor;
 use slog::{debug, o, trace};
 use std::sync::Arc;
 use tokio::sync::mpsc;
+use tokio_stream::wrappers::UnboundedReceiverStream;
 use types::EthSpec;
 
 /// Handles messages received from the network and client and organises syncing. This
@@ -101,7 +102,7 @@ impl<T: BeaconChainTypes> Router<T> {
         executor.spawn(
             async move {
                 debug!(log, "Network message router started");
-                handler_recv
+                UnboundedReceiverStream::new(handler_recv)
                     .for_each(move |msg| future::ready(handler.handle_message(msg)))
                     .await;
             },

beacon_node/network/src/service.rs

@@ -266,7 +266,7 @@ fn spawn_service<T: BeaconChainTypes>(
                     info!(service.log, "Network service shutdown");
                     return;
                 }
-                _ = service.metrics_update.next() => {
+                _ = service.metrics_update.tick() => {
                     // update various network metrics
                     metric_update_counter +=1;
                     if metric_update_counter % T::EthSpec::default_spec().seconds_per_slot == 0 {
@@ -283,7 +283,7 @@ fn spawn_service<T: BeaconChainTypes>(
                     metrics::update_sync_metrics(&service.network_globals);
 
                 }
-                _ = service.gossipsub_parameter_update.next() => {
+                _ = service.gossipsub_parameter_update.tick() => {
                     if let Ok(slot) = service.beacon_chain.slot() {
                         if let Some(active_validators) = service.beacon_chain.with_head(|head| {
                                 Ok::<_, BeaconChainError>(