User-agent:
    Compares the performance of the event system (goog.events.*)
    with the goog.pubsub.PubSub class.
  
The baseline test creates 1000 event targets and 1000 objects that handle events dispatched by the event targets, and has each event target dispatch 2 events 5 times each.
    The single-PubSub test creates 1000 publishers, 1000
    subscribers, and a single pubsub channel.  Each subscriber subscribes to
    topics on the same pubsub channel.  Each publisher publishes 5 messages to
    2 topics each via the pubsub channel.
  
    The multi-PubSub test creates 1000 publishers that are
    subclasses of goog.pubsub.PubSub and 1000 subscribers.  Each
    subscriber subscribes to its own publisher.  Each publisher publishes 5
    messages to 2 topics each via its own pubsub channel.