jakesmith/HPCC-Platform — comment on commit 415bcef54355f98417ba0b348d945f75942f83a1
File: thorlcr/activities/nsplitter/thnsplitterslave.cpp line 252
By jakesmith:

It's tracking which 'io' index, as tracked by 'o'. And using that 'o' in code that follows.
Only reason io is set, is to ensure found, i.e. the assert.