code: function accumulateTwoPhaseDispatchesSingle(event) {
    if (event && event.dispatchConfig.phasedRegistrationNames) {
      EventPluginUtils.traverseTwoPhase(event._targetInst, accumulateDirectionalDispatches, event);
    }
  }
docs: Collect dispatches (must be entirely collected before dispatching - see unit
  tests). Lazily allocate the array to conserve memory.  We must loop through
  each event and perform the traversal for each one. We cannot perform a
  single traversal for the entire collection of events because each event may
  have a different target.