drogon find crashed?

你好，我调用drogon的时候崩溃，崩溃的堆栈信息是：

```
(gdb) where
#0 0x00007ff6c2fc87ce in Json::Value::find(char const*, char const*) const () from /usr/local/lib/libjsoncpp.so.25
#1 0x00007ff6c2fc9a33 in Json::Value::operator[](char const*) const () from /usr/local/lib/libjsoncpp.so.25
#2 0x00007ff6c2fbd6db in Json::CharReaderBuilder::newCharReader() const () from /usr/local/lib/libjsoncpp.so.25
#3 0x00007ff6c332f83d in drogon::HttpResponseImpl::parseJson() const () from /usr/local/lib/libcurl_util.so
#4 0x00007ff6c3303576 in drogon::HttpClientImpl::handleResponse(std::shared_ptr const&, std::pair, std::function const&)> >&&, std::shared_ptr const&) () from /usr/local/lib/libcurl_util.so
#5 0x00007ff6c33038a4 in drogon::HttpClientImpl::onRecvMessage(std::shared_ptr const&, trantor::MsgBuffer*) () from /usr/local/lib/libcurl_util.so
#6 0x00007ff6c3303c08 in std::_Function_handler const&, trantor::MsgBuffer*), drogon::HttpClientImpl::createTcpClient()::{lambda(std::shared_ptr const&, trantor::MsgBuffer*)#1}>::_M_invoke(std::_Any_data const&, std::shared_ptr const&, trantor::MsgBuffer*&&) () from /usr/local/lib/libcurl_util.so
#7 0x00007ff6c33d8f64 in trantor::TcpConnectionImpl::onSslMessage(trantor::TcpConnection*, trantor::MsgBuffer*) () from /usr/local/lib/libcurl_util.so
#8 0x00007ff6c33e88cc in OpenSSLProvider::processApplicationData() () from /usr/local/lib/libcurl_util.so
#9 0x00007ff6c33ed383 in OpenSSLProvider::recvData(trantor::MsgBuffer*) () from /usr/local/lib/libcurl_util.so
#10 0x00007ff6c33dd545 in trantor::TcpConnectionImpl::readCallback() () from /usr/local/lib/libcurl_util.so
#11 0x00007ff6c33d1228 in trantor::Channel::handleEventSafely() () from /usr/local/lib/libcurl_util.so
#12 0x00007ff6c33d12c1 in trantor::Channel::handleEvent() () from /usr/local/lib/libcurl_util.so
#13 0x00007ff6c33c0f4c in trantor::EventLoop::loop() () from /usr/local/lib/libcurl_util.so
#14 0x00007ff6c33c1eb0 in trantor::EventLoopThread::loopFuncs() () from /usr/local/lib/libcurl_util.so
#15 0x00007ff6c28f8b23 in execute_native_thread_routine () from /lib64/libstdc++.so.6
#16 0x00007ff6c2d911ca in start_thread () from /lib64/libpthread.so.0
#17 0x00007ff6c1f10e73 in clone () from /lib64/libc.so.6
```

请问一下，什么情况下会出现这种错误呢，出现之后有啥处理办法可以不crash，感谢