func (c *Connection) handlePingRes(frame *Frame) bool {
	if err := c.outbound.forwardPeerFrame(frame); err != nil {
		c.log.WithFields(LogField{"response", frame.Header}).Warn("Unexpected ping response.")
		return true
	}
	// ping req is waiting for this frame, and will release it.
	return false
}
func (c *Connection) handlePingRes(frame *Frame) bool {
	if err := c.outbound.forwardPeerFrame(frame); err != nil {
		c.log.WithFields(LogField{"response", frame.Header}).Warn("Unexpected ping response.")
		return true
	}
	// ping req is waiting for this frame, and will release it.
	return false
}
// handlePingRes calls registered ping handlers.