minify
Minifies a VTIMEZONE so that only these observances are kept:
the last STANDARD observance matching startTemporal, and
the last DAYLIGHT observance matching startTemporal, and
observances beginning after startTemporal
Additionally, all properties other than observances and TZID are dropped.
Return
minified time zone definition
Parameters
original
time zone definition to minify
start
start date for components (usually DTSTART); null if unknown