How to execute a Greasemonkey script on every infinite scrolling event in a Twitter conversation?

I'm trying to make a greasemonkey userscript that will work in Twitter conversations

(colorize names,usernames and each 1st @reply).

When a Twitter conversation has a lot of replies (example link),

then opening such a link displays only 3 screenfuls of replies(the initial screenful+2 more)

-at least in my 1920x1200 display- and then you have to scroll down manually in order to see the rest of replies.

How can I make my script executed on every infinite scrolling event (on every Mousewheel down or PgDn or Down arrow ↓ keypress)?

Someone has kindly suggested:

Try inspecting the code in FF devtools debugger (right click the code and choose 'prettify source') to see how infiniteScrollWatcher is triggered

So, I suppose that I should bind an event listener to this function using EventTarget.addEventListener, but I don't know how (this function is way too advanced for me).

The prettified source of that function is:

function infiniteScrollWatcher() {
  var a = 0,
  b = 1;
  this.checkScrollPosition = function () {
    var c = this.webkitFullscreenElement();
    if (c && this.node != c && !c.contains(this.node)) return;
    var d = this.$content.height(),
    e = !1;
    this.inTriggerRange(a) && (d > this.lastTriggeredHeight || this.lastTriggeredFrom(b)) ? (this.trigger('uiNearTheTop'), this.lastTriggerFrom = a, e = !0)  : this.inTriggerRange(b) && (d > this.lastTriggeredHeight || this.lastTriggeredFrom(a)) && (this.trigger('uiNearTheBottom'), this.lastTriggerFrom = b, e = !0),
    e && (this.lastTriggeredHeight = d)
  },
  this.inTriggerRange = function (c) {
    var d = this.$content.height(),
    e = this.$node.scrollTop(),
    f = e + this.$node.height(),
    g = Math.abs(Math.min(f - d, 0)),
    h = this.$node.height() / 2;
    return e < h && c == a || g < h && c == b
  },
  this.lastTriggeredFrom = function (a) {
    return this.lastTriggerFrom === a
  },
  this.resetScrollState = function () {
    this.lastTriggeredHeight = 0,
    this.lastTriggerFrom = - 1
  },
  this.webkitFullscreenElement = function () {
    return document.webkitFullscreenElement
  },
  this.after('initialize', function () {
    this.resetScrollState(),
    this.$content = this.attr.contentSelector ? this.select('contentSelector')  : $(document),
    this.on('scroll', utils.throttle(this.checkScrollPosition.bind(this), 100)),
    this.on('uiTimelineReset', this.resetScrollState),
    this.on('uiSwiftLoaded uiPageChanged', this.checkScrollPosition)
  })
}