message: start and end time of agent track info are always integers
diff: @@ -8,8 +8,8 @@ class AgentTrackInfo:
  def __init__(self, filename, track_id, start_offset, end_offset, first_ts_on_map=None):
  self._filename = filename
  self._track_id = track_id # TODO: rename to agent_id
  - self._start_offset = start_offset # TODO: rename to start_time
  - self._end_offset = end_offset # TODO: rename to end_time
  + self._start_offset = int(start_offset) # TODO: rename to start_time
  + self._end_offset = int(end_offset) # TODO: rename to end_time
  def __str__(self):
  return 'id={} start_offset={} end_offset={}'.format(self._track_id, self._start_offset, self._end_offset)
  