Fix memory leak in client/server mapping (#71)

src/client.rs

@@ -434,6 +434,8 @@ impl Client {
                             server.query("DISCARD ALL").await?;
                         }
 
+                        self.release();
+
                         return Ok(());
                     }
 

src/pool.rs

@@ -209,8 +209,6 @@ impl ConnectionPool {
             let index = self.round_robin % addresses.len();
             let address = &addresses[index];
 
-            self.stats.client_waiting(process_id, address.id);
-
             // Make sure you're getting a primary or a replica
             // as per request. If no specific role is requested, the first
             // available will be chosen.
@@ -224,6 +222,9 @@ impl ConnectionPool {
                 continue;
             }
 
+            // Indicate we're waiting on a server connection from a pool.
+            self.stats.client_waiting(process_id, address.id);
+
             // Check if we can connect
             let mut conn = match self.databases[shard][index].get().await {
                 Ok(conn) => conn,