void ProtocolV1::send_keepalive() {
  ldout(cct, 10) << __func__ << dendl;
  std::lock_guard<std::mutex> l(connection->write_lock);
  if (can_write != WriteStatus::CLOSED) {
    keepalive = true;
    connection->center->dispatch_event_external(connection->write_handler);
  }
}
Unknown