The websocket standard allows sending arbitrary pong frames at any time
as a unidirectional heartbeat. With the connection's previous
implementation of websocket pinging, this would result in a disconnect
because the connection thought the server had missed its pong.
The current implementation only results in false positives, not
negatives, if the server accidentally sends an unprompted pong with the
same payload as our last ping. It can be debated whether this is an
actual *false* positive or just a plain positive though as the server is
still alive.
