Add support to client transports for requests that may result in multiple

responses. (#377)

This adds ComposeRequestMulti and other *Multi types. The main change is to
the stream transport, which is the only transport that implements
SendRequestMulti.

tests/net-client-cache.rs

@@ -84,7 +84,7 @@ async fn test_transport_error() {
     let mut msg = msg.question();
     msg.push((Name::vec_from_str("example.com").unwrap(), Rtype::AAAA))
         .unwrap();
-    let req = RequestMessage::new(msg);
+    let req = RequestMessage::new(msg).unwrap();
 
     let mut request = cached.send_request(req.clone());
     let reply = request.get_response().await;

tests/net-client.rs

@@ -11,6 +11,7 @@ use domain::net::client::dgram;
 use domain::net::client::dgram_stream;
 use domain::net::client::multi_stream;
 use domain::net::client::redundant;
+use domain::net::client::request::RequestMessageMulti;
 use domain::net::client::stream;
 use std::fs::File;
 use std::net::IpAddr;
@@ -43,7 +44,8 @@ fn single() {
         let step_value = Arc::new(CurrStepValue::new());
 
         let conn = Connection::new(stelline.clone(), step_value.clone());
-        let (octstr, transport) = stream::Connection::new(conn);
+        let (octstr, transport) =
+            stream::Connection::<_, RequestMessageMulti<Vec<u8>>>::new(conn);
         tokio::spawn(async move {
             transport.run().await;
         });
@@ -138,7 +140,10 @@ fn tcp() {
             }
         };
 
-        let (tcp, transport) = stream::Connection::new(tcp_conn);
+        let (tcp, transport) = stream::Connection::<
+            _,
+            RequestMessageMulti<Vec<u8>>,
+        >::new(tcp_conn);
         tokio::spawn(async move {
             transport.run().await;
             println!("single TCP run terminated");