Dropping late data in DirectRunner

[Jan Lukavský]

Hi,

I just found out that DirectRunner is apparently not using 
LateDataDroppingDoFnRunner, which means that it doesn't drop late data 
in cases where there is no GBK operation involved (dropping in GBK seems 
to be correct). There is apparently no @Category(ValidatesRunner) test 
for that behavior (because DirectRunner would fail it), so the question 
is - should late data dropping be considered part of model (of which 
DirectRunner should be a canonical implementation) and therefore that 
should be fixed there, or is the late data dropping an optional feature 
of a runner?

I'm strongly in favor of the first option, and I think it is likely that 
all real-world runners would probably adhere to that (I didn't check 
that, though).

Opinions?

 Jan