aquatic_http: add keep_alive setting (default true)

This might be good for performance in the real world. It also
enables fairer load test comparisons with opentracker, which
in my understanding drops connections after sending responses.

aquatic_http/src/lib/config.rs

@@ -55,6 +55,7 @@ pub struct NetworkConfig {
     pub ipv6_only: bool,
     #[serde(flatten)]
     pub tls: TlsConfig,
+    pub keep_alive: bool,
     pub poll_event_capacity: usize,
     pub poll_timeout_microseconds: u64,
 }
@@ -128,6 +129,7 @@ impl Default for NetworkConfig {
             address: SocketAddr::from(([0, 0, 0, 0], 3000)),
             ipv6_only: false,
             tls: TlsConfig::default(),
+            keep_alive: true,
             poll_event_capacity: 4096,
             poll_timeout_microseconds: 10_000,
         }

aquatic_http/src/lib/network/mod.rs

@@ -115,6 +115,7 @@ pub fn run_poll_loop(
 
         if !(local_responses.is_empty() & (response_channel_receiver.is_empty())) {
             send_responses(
+                &config,
                 &mut response_buffer,
                 local_responses.drain(..),
                 response_channel_receiver.try_iter(),
@@ -304,6 +305,7 @@ pub fn handle_connection_read_event(
 
 /// Read responses from channel, send to peers
 pub fn send_responses(
+    config: &Config,
     buffer: &mut Cursor<&mut [u8]>,
     local_responses: Drain<(ConnectionMeta, Response)>,
     channel_responses: crossbeam_channel::TryIter<(ConnectionMeta, Response)>,
@@ -327,7 +329,9 @@ pub fn send_responses(
                 Ok(()) => {
                     debug!("sent response");
 
-                    // established.shutdown();
+                    if !config.network.keep_alive {
+                        connections.remove(&meta.poll_token);
+                    }
                 },
                 Err(err) if err.kind() == ErrorKind::WouldBlock => {
                     debug!("send response: would block");