pub fn parse_micros(amount: &str) -> Option<Micros>Expand description
A decimal string as millionths, or None when it is not one.
Integer-only: "3.5" is 3_500_000, not a float that might be 3.4999999.
More than six fractional digits is a price this format cannot represent
exactly, so it is refused rather than rounded behind the operator’s back.