on (event, callback) {
    if (!event || !callback || !this.player) {
      showErrorMsg(this.pluginName, 'plugin.on(event, callback)')
      return
    }
    if (typeof event === 'string') {
      this.__events[event] = callback
      this.player.on(event, callback)
    } else if (Array.isArray(event)) {
      event.forEach((item) => {
        this.__events[item] = callback
        this.player.on(item, callback)
      })
    }
  }
@param { string | Array<string> } event
@param { Function } callback
@returns