code: @Test public void testSetter() throws URISyntaxException {
    WebSocketClient client=new WebSocketClient(new URI("ws://localhost")){
      @Override public void onOpen(    ServerHandshake handshakedata){
      }
      @Override public void onMessage(    String message){
      }
      @Override public void onClose(    int code,    String reason,    boolean remote){
      }
      @Override public void onError(    Exception ex){
      }
    }
  ;
    assertNull(client.<WebSocketClient>getAttachment());
    client.setAttachment(client);
    assertEquals(client.<WebSocketClient>getAttachment(),client);
    client.setAttachment(null);
    assertNull(client.<WebSocketClient>getAttachment());
  }
  