Audit Balance and Control

The sample applications use a simplistic counts['stage'] += 1 to accumulate balance information.

After spending some quality time reviewing Audit Balance and Control designs, it's time to update the demo programs to reflect a slightly smarter approach to this.

We don't need to go all the way down the ABC road -- yet -- but we do need to acknowledge that the balances need to reflect something we can call the "ABC Invariant".

The following must be true: count['read'] == count['invalid'] + count['rejected'] + count['processed']

We need to upgrade the demo programs to reflect this essential rule in a consistent way. We can then persist the counts (and sums and other aggregate functions) for control purposes.