often times, we'll filter variants on the quality or something.
I think it'd be nice to send the info to _Record as a string and
have .INFO be a property that parses the string on first access.
This could improve the speed.
I will look at this when I have time. you don't need promise, you can just use a property
if not self._info:
self._info = _parse_info_string(self._info_string)
Closing as my profiling script indicates <0.1 % of time spent in this function. The real action is in #25.