swarm/src/connection: update dial concurrency factor default value to > 8 (libp2p#2678)

Author: maschad

swarm/CHANGELOG.md

@@ -6,9 +6,11 @@
 
 - Remove `connection::ListenersStream` and poll the `Transport` directly. See [PR 2652].
 
+- Update dial address concurrency factor to `8`, thus dialing up to 8 addresses concurrently for a single connection attempt. See `Swarm::dial_concurrency_factor` and [PR 2741].
+
 [PR 2716]: https://github.com/libp2p/rust-libp2p/pull/2716/
 [PR 2652]: https://github.com/libp2p/rust-libp2p/pull/2652
-
+[PR 2741]: https://github.com/libp2p/rust-libp2p/pull/2741/
 # 0.36.1
 
 - Limit negotiating inbound substreams per connection. See [PR 2697].

swarm/src/connection/pool.rs

@@ -1175,8 +1175,8 @@ impl Default for PoolConfig {
             executor: None,
             task_event_buffer_size: 32,
             task_command_buffer_size: 7,
-            // By default, addresses of a single connection attempt are dialed in sequence.
-            dial_concurrency_factor: NonZeroU8::new(1).expect("1 > 0"),
+            // Set to a default of 8 based on frequency of dialer connections
+            dial_concurrency_factor: NonZeroU8::new(8).expect("8 > 0"),
             substream_upgrade_protocol_override: None,
             max_negotiating_inbound_streams: 128,
         }