message: modify emit position
diff: },
  _initPullDownRefresh() {
  this.scroll.on('pullingDown', () => {
  - this.$emit('pullingDown')
  this.beforePullDown = false
  this.isPullingDown = true
  this.pulling = true
  + this.$emit('pullingDown')
  })
  this.scroll.on('scroll', (pos) => {
  },
  _initPullUpLoad() {
  this.scroll.on('pullingUp', () => {
  - this.$emit('pullingUp')
  this.isPullUpLoad = true
  + this.$emit('pullingUp')
  })
  },
  _reboundPullDown() {
  