First of all, for a well-behaved client, such as portal, it will do the right thing.  Meaning the delta that it sent will only contains those of interesting path and this code should not get hit.   I put this code in on the server for defense-in-depth.  As far as statistic goes, since the total (simple delta.count) includes this, we have to consider those ignored as progress.  I originally introduced an ignoredCount but I think it is overkilled as far as stat goes.

unless we count the total filter with path.  It seems unnecessarily complicated and likely useless given we only have good client.