Remove network lock (#840)

* Initial work on removing libp2p lock

* Removes lock from libp2p service

* Completed network lock removal

* Correct network termination future

* Correct fmt issues

* Remove Drop implementation for network service

* Address reviewers suggestions

* Fix dht persistence test (#844)

* Fix persistence test

* Block until dht is persisted

* Fix libp2p test

* Correct test ordering check

* Remove expensive tests from debug testing

Co-authored-by: Pawan Dhananjay <pawandhananjay@gmail.com>

beacon_node/eth2-libp2p/src/globals.rs

@@ -0,0 +1,30 @@
+//! A collection of variables that are accessible outside of the network thread itself.
+use crate::{Enr, Multiaddr, PeerId};
+use parking_lot::RwLock;
+use std::collections::HashSet;
+use std::sync::atomic::AtomicUsize;
+
+pub struct NetworkGlobals {
+    /// The current local ENR.
+    pub local_enr: RwLock<Option<Enr>>,
+    /// The local peer_id.
+    pub peer_id: RwLock<PeerId>,
+    /// Listening multiaddrs.
+    pub listen_multiaddrs: RwLock<Vec<Multiaddr>>,
+    /// Current number of connected libp2p peers.
+    pub connected_peers: AtomicUsize,
+    /// The collection of currently connected peers.
+    pub connected_peer_set: RwLock<HashSet<PeerId>>,
+}
+
+impl NetworkGlobals {
+    pub fn new(peer_id: PeerId) -> Self {
+        NetworkGlobals {
+            local_enr: RwLock::new(None),
+            peer_id: RwLock::new(peer_id),
+            listen_multiaddrs: RwLock::new(Vec::new()),
+            connected_peers: AtomicUsize::new(0),
+            connected_peer_set: RwLock::new(HashSet::new()),
+        }
+    }
+}