Adds observer to receive callbacks for pong events.
Iterates through each observer, so that their notification functions may be called.
Handles the events from the SignalingClient this observer is registered with.
The event being notified.
Removes observer to stop receiving callbacks for pong events.
Starts sending pings on an interval and receiving pongs.
Stops ping-pongs.
[[DefaultPingPong]] implements the PingPong and SignalingClientObserver interface.