code: function _toast () {
    let _instance = new ToastInstance(ToastComponent, 'toastPortal')
    // 自动开启
    let _args = Array.prototype.slice.call(arguments)
    _instance.present(..._args)
    return _instance
  }
docs: 对外的Toast构建部分
  @function present
  @description 打开Toast
  @param {object} args - 传入参数
  @param {string} args.message - The message for the toast. Long strings will wrap and the toast container will
  expand.
  @param {number} [args.duration=3000] - How many milliseconds to wait before hiding the toast.
  @param {string} [args.position="bottom"] - The position of the toast on the screen. Accepted values: "top",
  "middle", "bottom".
  @param {string} [args.cssClass] - Additional classes for custom styles, separated by spaces.
  @param {boolean} [args.showCloseButton=false] - Whether or not to show a button to close the toast.
  @param {string} [args.closeButtonText='Close'] - Text to display in the close button.
  @param {boolean} [args.dismissOnPageChange=false] - Whether to dismiss the toast when navigating to a new page or
  nav back.
  @return {ToastInstance} 返回Toast的实例
  @private