ping requests are sent even when traffic is ongoing

socketcluster would send ping requests (and expect responses in time) even when traffic is ongoing on a connection. In general, ping keep-alive packets have two purposes:

• to check whether the peer is still there, e.g. to check that he has not dropped / crashed / disconnected from the network
• to keep the state in stateful firewalls

so, it does not make sense to send keep-alive packets when other traffic is being transmitted over the connection. It only makes sense when the connection is otherwise idle. From https://en.wikipedia.org/wiki/Keepalive:

Typically TCP Keepalives are sent every 45 or 60 seconds on an idle TCP connection

On top of being useless, the behavior can cause disconnects due to bogus ping timeouts when heavy traffic is being transmitted - the ping packets could get delayed beyond pingTimeout if lots of data is being sent/received.

Start by tracing SocketCluster's ping and keep-alive handling, then reproduce a connection under sustained traffic to observe ping timing and timeout behavior. The change is done when keep-alive pings are sent only for otherwise idle connections and active traffic cannot cause bogus ping timeouts.