♻️ refactor: move the last request-response pair into protocol mod

still need to move a couple handle pairs

prototypes/quic_demo/src/bin/quic_demo_end_server.rs

@@ -2,7 +2,6 @@ use structopt::StructOpt;
 use tokio::net::TcpStream;
 
 use quic_demo::prelude::*;
-use protocol::Command;
 
 #[derive (Debug, StructOpt)]
 struct Opt {

prototypes/quic_demo/src/bin/quic_demo_relay_server.rs

@@ -314,24 +314,7 @@ async fn handle_p4_connection (
 			
 			debug! ("P4 {} got a request from P2 {}", server_id, req.client_id);
 			
-			let (mut server_send, mut server_recv) = connection.open_bi ().await?;
-			
-			let req_buf = [
-				Command::CONNECT_P2_TO_P4_STEP_2.0,
-				client_id,
-				0,
-				0,
-			];
-			server_send.write_all (&req_buf).await?;
-			
-			let mut resp_buf = [0, 0, 0, 0];
-			server_recv.read_exact (&mut resp_buf).await?;
-			assert_eq! (resp_buf, [
-				Command::OKAY.0,
-				Command::CONNECT_P2_TO_P4_STEP_2.0,
-				0,
-				0,
-			]);
+			let (server_send, server_recv) = protocol::p3_connect_p2_to_p4 (&connection, client_id).await?;
 			
 			trace! ("Relaying bytes...");
 			

prototypes/quic_demo/src/protocol.rs

@@ -64,6 +64,29 @@ pub async fn p2_connect_to_p5 (
 	Ok ((send, recv))
 }
 
+pub async fn p3_connect_p2_to_p4 (
+	connection: &quinn::Connection,
+	client_id: u8,
+) -> Result <(SendStream, RecvStream)>
+{
+	let (mut send, mut recv) = connection.open_bi ().await?;
+	
+	let cmd_type = Command::CONNECT_P2_TO_P4_STEP_2.0;
+	
+	let buf = [
+		cmd_type,
+		client_id,
+		0,
+		0,
+	];
+	send.write_all (&buf).await?;
+	
+	expect_exact_response (&mut recv, [Command::OKAY.0, cmd_type, 0, 0]).await
+	.context ("P3 didn't get OK response when asking P4 to connect P2 to P4")?;
+	
+	Ok ((send, recv))
+}
+
 pub async fn p4_connect_to_p3 (
 	endpoint: &quinn::Endpoint,
 	relay_addr: &std::net::SocketAddr,