Can't follow starting from a particular time of day

[jlee-made]

This is documented behaviour but seems to leave an important use case unsupported:

There seems to be no way to follow (tail) logs, skipping over a certain time period, because say you had a million errors from some bug and you can't/don't want to tail through all those:

• Trigger a lot of logs somehow

• Stop triggering lots of logs

• elktail --url elasticsearch.example.com -f '%@timestamp %@message' -- '+@message:"error"'
  -> All the errors (for today's date, I guess?) are printed

• elktail --url elasticsearch.example.com -a '2017-04-20T11:20:00' -f '%@timestamp %@message' -- '+@message:"error"'
  Expect:
  -> elktail does not print all the errors
  -> elktail tails forever
  Got:
  -> elktail does not print all the errors
  -> elktail exits

So it would be nice if when there's an -a (but no -b), elktail could tail (either always or when an extra flag is given).