message: optimize autoPullDownRefresh
diff: @@ -41,13 +41,13 @@ export function pullDownMixin(BScroll) {
  BScroll.prototype.autoPullDownRefresh = function () {
  const { threshold = 90, stop = 40 } = this.options.pullDownRefresh
  - this.scrollTo(this.x, threshold)
  -
  - if (!this.pulling) {
  - this.pulling = true
  - this.trigger('pullingDown')
  + if (this.pulling) {
  + return
  }
  + this.pulling = true
  + this.scrollTo(this.x, threshold)
  + this.trigger('pullingDown')
  this.scrollTo(this.x, stop, this.options.bounceTime, ease.bounce)
  }
  }
  