Does anyone have any way to get network usage similar to the iStats Menu widget? I'm using https://github.com/marekkaczkowski/Touch-Bar-iStats to try and replace the menu applets and am looking for something similar to the iostat utility.
iStats can't do this, it's limited to some basic information (see here).
You could try to find a workaround with
nettop
but only with a lot of work I fear.
I was referring to https://bjango.com/mac/istatmenus/, a menu bar app that does lots of pretty graphs and stats.
I'm thinking the best solution might be to run something like netstat -i -b -w 1, but it doesn't have a count flag like vm_stat does.
Damn my bad 
can't help you though with this program, but I'll look into MenuMeters (what I'm using to color up my menu bar with these information) and come back with the result.