Upgrade tokio to 1.22.0 and replace async-std with tokio (#12646)

* Replace deprecated libp2p feature specs with correct ones

* Bump tokio to 1.21.2

* Replace async-std libp2p primitives with tokio ones

* minor: rustfmt

* Fix TestNet to run initialization in the tokio context

* Convert telemetry test from async-std to tokio

* Convert notifications tests from async-std to tokio

* Convert chain sync tests from async-std to tokio

* Ditch async-std completely

* Make executor mandatory

* Bump tokio to 1.22.0

* minor: rustfmt

* Explicitly use tokio runtime in tests

* Move more tests to explicit tokio runtime

* Explicitly set multithreaded runtime in tokio test

* minor: rustfmt

* minor: fix comment

* Replace async-std with tokio in MMR tests

substrate/client/network/src/discovery.rs

@@ -64,7 +64,7 @@ use libp2p::{
 		GetClosestPeersError, Kademlia, KademliaBucketInserts, KademliaConfig, KademliaEvent,
 		QueryId, QueryResult, Quorum, Record,
 	},
-	mdns::{Mdns, MdnsConfig, MdnsEvent},
+	mdns::{MdnsConfig, MdnsEvent, TokioMdns},
 	multiaddr::Protocol,
 	swarm::{
 		behaviour::toggle::{Toggle, ToggleIntoConnectionHandler},
@@ -235,7 +235,7 @@ impl DiscoveryConfig {
 			allow_private_ipv4,
 			discovery_only_if_under_num,
 			mdns: if enable_mdns {
-				match Mdns::new(MdnsConfig::default()) {
+				match TokioMdns::new(MdnsConfig::default()) {
 					Ok(mdns) => Some(mdns),
 					Err(err) => {
 						warn!(target: "sub-libp2p", "Failed to initialize mDNS: {:?}", err);
@@ -266,7 +266,7 @@ pub struct DiscoveryBehaviour {
 	/// it's always enabled in `NetworkWorker::new()`.
 	kademlia: Toggle<Kademlia<MemoryStore>>,
 	/// Discovers nodes on the local network.
-	mdns: Option<Mdns>,
+	mdns: Option<TokioMdns>,
 	/// Stream that fires when we need to perform the next random Kademlia query. `None` if
 	/// random walking is disabled.
 	next_kad_random_query: Option<Delay>,