lib/events.js
function addListener(id, event, listener) {
    if (!hasListeners(event)) {
      context._events[event] = {};
    }
    
    context._events[event][id] = listener;

    return id;
  }
function addListener(id, event, listener) {
    if (!hasListeners(event)) {
      context._events[event] = {};
    }
    
    context._events[event][id] = listener;

    return id;
  }
function addListener ( id , event , listener ) { if ( ! hasListeners ( event ) ) { context . _events [ event ] = { } ; } context . _events [ event ] [ id ] = listener ; return id ; }
adds a listener to an event
adds a listener to an event