I have looked at the code, and I believe the "timeFilter" equates to the "time" option found on the ArcREST API Query Feature Service page. It gives 3 examples with a little explanation:
time=1199145600000
time=1199145600000, 1230768000000
time=null, 1230768000000
When I experimented with this, the query always returned all rows. My records have a CreateDate and an EditDate field, so I am not sure what the "timeFilter" or "time" option is doing.
I did use this line of code in the github code to successfully retrieve records after a specific date/time:
print (fl.query(where="EditDate > DATE '2016-05-29 18:30:00'",out_fields='*',returnGeometry=False) )