docs: protected boolean setChannel(final Channel newChannel) {
          if(newChannel == null) {
              return false;
          }
          synchronized (lock) {
              if(state != State.OPEN || channel != null) {
                  return false;
              }
              this.channel = newChannel;
              this.channel.addCloseHandler(new CloseHandler<Channel>() {
                  @Override
                  public void handleClose(final Channel closed, final IOException exception) {
                      synchronized (lock) {
                          if(FutureManagementChannel.this.channel == closed) {
                              FutureManagementChannel.this.channel = null;
                          }
                          lock.notifyAll();
                      }
                  }
              });
              lock.notifyAll();
              return true;
          }
      }