@Override
    public String toString() {
        return "Replicator [state=" + getState() + ", statInfo=" + this.statInfo + ", peerId="
                + this.options.getPeerId() + ", groupId=" + this.options.getGroupId() + ", waitId=" + this.waitId
                + ", type=" + this.options.getReplicatorType() + "]";
    }
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