OptionallookaheadOptionaloffsetRead the bucket completed this many buckets ago. Default 0, the current one.
OptionalsessionA session window, '0915-1530', that anchors sub-day buckets to the
session open instead of the epoch. Without it a 30-minute bucket on a
09:15 open runs 09:00 to 09:30; with it, 09:15 to 09:45.
OptionaltimezoneThe calendar the buckets are cut in. Defaults to the shipped default zone.
Read each bucket's final values on all of its bars. Default false.