Results 3 issues of vicvon

当redis cluster中主节点和对应的从节点为`disconnected`状态,通过`redis_cluster::cluster_nodes`获取到的节点信息会丢失`disconnected`节点的信息。 例如 ``` 29fe8907fda427676f1092c3a12e8f96fc9edfe5 127.0.0.1:16384 master - 0 1568875198663 100 connected 5462-10922 d4935a663f6d478a8ad45591a0290ad71c8a17bc 127.0.0.1:16380 slave,fail ec41b3d85747a55c0931b08613f01e28d73e9fe5 1568861725574 1568861724572 109 disconnected cd3b773beb86818243bb20bc571c31dd3b366e13 127.0.0.1:16382 master - 0 1568875199666 99 connected 10923-16383...

There is a problem with the UAS state machine,while a CANCEL request send by UAC for pending INVITE, the goroutine leaks. ![微信截图_20220801164927](https://user-images.githubusercontent.com/13044301/182110925-709f093a-5c28-4b4f-8641-c16538ce3509.png)

I am using visual studio code on windows and I only install c++clang extension and cpptools extension, but c++clang extension autocomplete does not work. I also use clang.cxxflags in configuration...