Method sendPing

nats.go:5764–5769

The lock must be held entering this function.

(ch chan struct{})

// The lock must be held entering this function.
func (nc *Conn) sendPing(ch chan struct{}) {
	nc.pongs = append(nc.pongs, ch)
	nc.bw.appendString(pingProto)
	// Flush in place.
	nc.bw.flush()
}

// This will fire periodically and send a client origin
// ping to the server. Will also check that we have received