Simplify connection count checking by reporting zero connections for …

…connection-less oriented server metrics.

src/net/server/metrics.rs

@@ -49,13 +49,14 @@ impl ServerMetrics {
 impl ServerMetrics {
     /// The number of current connections, if applicable.
     ///
-    /// This will be None for connection-less servers such as [`DgramServer`].
+    /// This will be zero for connection-less servers such as [`DgramServer`].
     ///
     /// [`DgramServer`]: crate::net::server::dgram::DgramServer
-    pub fn num_connections(&self) -> Option<usize> {
+    pub fn num_connections(&self) -> usize {
         self.num_connections
             .as_ref()
             .map(|atomic| atomic.load(Ordering::Relaxed))
+            .unwrap_or_default()
     }
 
     /// Set the number of current connections metric.

src/net/server/stream.rs

@@ -523,10 +523,7 @@ where
                 accept_res = self.accept() => {
                     match accept_res {
                         Ok((stream, addr)) => {
-                            // SAFETY: This is a connection-oriented server so there
-                            // must always be a connection count metric avasilable to
-                            // unwrap.
-                            let num_conn = self.metrics.num_connections().unwrap();
+                            let num_conn = self.metrics.num_connections();
                             if num_conn < self.config.load().max_concurrent_connections {
                                 self.spawn_connection_handler(stream, addr);
                             }

src/net/server/tests.rs

@@ -414,7 +414,7 @@ async fn service_test() {
 
         // Verify that no requests or responses are in progress still in
         // the server.
-        assert_eq!(srv.metrics().num_connections(), Some(0));
+        assert_eq!(srv.metrics().num_connections(), 0);
         assert_eq!(srv.metrics().num_inflight_requests(), 0);
         assert_eq!(srv.metrics().num_pending_writes(), 0);
         assert_eq!(srv.metrics().num_received_requests(), num_messages);