[FEATURE] info metric for total bytes sent/received by command in # commandstats

[SoftlyRaining]

Metrics for total bytes sent/received would be useful to calculate average command size over time, which would be helpful to diagnose whether command size is the cause of high latency/cpu/buffer size. I may find time to implement it myself but I wanted to see what the community thinks first 🙂

I am aware of commandlog heavytraffic but this would provide a more complete historical view.