js/leaflet.markercluster.js
function (fn) {
    this._queue.push(fn);
    if (!this._queueTimeout) {
      this._queueTimeout = setTimeout(L.bind(this._processQueue, this), 300);
    }
  }
function (fn) {
    this._queue.push(fn);
    if (!this._queueTimeout) {
      this._queueTimeout = setTimeout(L.bind(this._processQueue, this), 300);
    }
  }
function ( fn ) { this . _queue . push ( fn ) ; if ( ! this . _queueTimeout ) { this . _queueTimeout = setTimeout ( L . bind ( this . _processQueue , this ) , 300 ) ; } }
Enqueue code to fire after the marker expand/contract has happened
Enqueue code to fire after the marker expand / contract has happened