CriticalSection has been fixed! Thanks

Thank you for the great analysis. (

This time, IPV6 is enabled as standard, and the placement of CriticalSection is changed.

Next time, we will implement RPC thread pool and verify with testnet.

In order to prevent deadlocks, we would like to put a mechanism like the message queue implemented in Windows.

The RPCs that need to proceed after processing has been processed reliably are like SendMessage, and if there are no problems asynchronously by accumulating in the queue with RPCs are processed efficiently with a mechanism like PostMessage.

Also, if we consider only the PostMessage part instead of thinking about the scope of CriticalSection, it can prevent deadlock even if it is complicated.