Feature Request: Graceful shutdown and graceful restart option
I hope this is in the right place... but I have a feature request for xmrig-proxy....

A graceful shutdown/restart option whereby when the shutdown request is received, xmrig-proxy 'waits' for workers to finish up their work and then stops accepting work from them. 

Process flow example using 2 mining rigs connecting to a proxy:

Graceful shutdown/restart request received:
1. echo "Shutdown request received... waiting for rigs to finish up...."
2. Rig #1 submits share, further shares blocked from that worker
3. Proxy knows 2 rigs are connected and waits for final share from Rig #2
4. Rig #2 submits share, xmrig-proxy blocks further shares and shuts down/restarts

Configurable option "Timeout" : Wait X number of seconds for shares when shutdown received.

Hopefully self-explanatory why I'm asking for this... but I'll explain anyway:

The idea here being that when the shutdown/restart request is received, the miners aren't losing the work they are currently doing.