static void onBlockTimeoutInNewThread(final ThreadId id) {
        if (id != null) {
            continueSending(id, RaftError.ETIMEDOUT.getNumber());
        }
    }
Send probe or heartbeat request
@param isHeartbeat      if current entries is heartbeat
@param heartBeatClosure heartbeat callback
jraft-core/src/main/java/com/alipay/sofa/jraft/core/Replicator.java