message: fix: Mqtt client close when not connected
diff: @@ -245,8 +245,8 @@ MqttClient.prototype.close = function (cb) {
  return new Promise((resolve) => {
  this.closed = true
  - if (this.client && (this.client.connected || this.client.reconnecting)) {
  - this.client.end(() => resolve())
  + if (this.client) {
  + this.client.end(!this.client.connected, () => resolve())
  } else {
  resolve()
  }
  