feat(perf): implement libp2p perf protocol

Implementation of the libp2p perf protocol according to https://github.com/libp2p/specs/pull/478/.

//CC @MarcoPolo  as the author of the specification.

**Don't (yet) expect this to produce reliable performance metrics.**

Pull-Request: #3508.

protocols/perf/tests/lib.rs

@@ -0,0 +1,62 @@
+// Copyright 2023 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+use libp2p_perf::{
+    client::{self, RunParams},
+    server,
+};
+use libp2p_swarm::{Swarm, SwarmEvent};
+use libp2p_swarm_test::SwarmExt;
+
+#[async_std::test]
+async fn perf() {
+    let _ = env_logger::try_init();
+
+    let mut server = Swarm::new_ephemeral(|_| server::Behaviour::new());
+    let server_peer_id = *server.local_peer_id();
+    let mut client = Swarm::new_ephemeral(|_| client::Behaviour::new());
+
+    server.listen().await;
+    client.connect(&mut server).await;
+
+    async_std::task::spawn(server.loop_on_next());
+
+    client
+        .behaviour_mut()
+        .perf(
+            server_peer_id,
+            RunParams {
+                to_send: 0,
+                to_receive: 0,
+            },
+        )
+        .unwrap();
+
+    client
+        .wait(|e| match e {
+            SwarmEvent::IncomingConnection { .. } => panic!(),
+            SwarmEvent::ConnectionEstablished { .. } => None,
+            SwarmEvent::Dialing(_) => None,
+            SwarmEvent::Behaviour(client::Event { result, .. }) => Some(result),
+            e => panic!("{e:?}"),
+        })
+        .await
+        .unwrap();
+}