Auto cancel loop watcher on destruct

lib/Server.php

@@ -59,6 +59,17 @@ public function __construct($socket, int $chunkSize = 65536) {
         Loop::disable($this->watcher);
     }
 
+    /**
+     * Automatically cancels the loop watcher.
+     */
+    public function __destruct() {
+        if (!$this->socket) {
+            return;
+        }
+
+        $this->free();
+    }
+
     /**
      * @return \Amp\Promise<ServerSocket|null>
      *
@@ -88,21 +99,28 @@ public function accept(): Promise {
      * Closes the server and stops accepting connections. Any socket clients accepted will not be closed.
      */
     public function close() {
-        Loop::cancel($this->watcher);
-
         if ($this->socket) {
             \fclose($this->socket);
         }
 
+        $this->free();
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAddress() {
+        return $this->address;
+    }
+
+    private function free() {
+        Loop::cancel($this->watcher);
+
         $this->socket = null;
 
         if ($this->acceptor) {
             $this->acceptor->resolve();
             $this->acceptor = null;
         }
     }
-
-    public function getAddress() {
-        return $this->address;
-    }
 }