[Feature Request] Add summary stats

[miketweaver]

As we were digging through large data, we were using the custom --query command to explore large pcaps. After an hour run, we found there were no results written.

It could be useful to add a feature that shows summary stats while the commands are running. Something like
"12 rows written", etc as the threads are completing. This would allow me to know that my command was returning 0 results and that I had made a mistake in my query.