OptionalcountOptionalfromInterval token, e.g. "1m", "5m", "1h", "D".
OptionalnoFetch authoritative history instead of a cached snapshot, when supported.
OptionalsignalCancel this consumer's request. Existing feeds may ignore cancellation.
OptionaltimeoutDeadline in milliseconds, including response-body reading. The shared request pool holds it to 2^31 - 1 ms, the longest a timer waits.
OptionaltoOptionalvariantWhich of the provider's series: a session, an adjustment, a currency or a
unit. Absent is the provider's default. A feed serves only what it
declares through dataVariants, and never derives one series from another.
Preferred number of bars; a date-range feed may return a different count.