Function fractional_time_to_span 

fn fractional_time_to_span(
    unit: Unit,
    value: i64,
    fraction: i32,
    span: Span,
) -> Result<Span, Error>

This routine returns a span based on the given unit and value with fractional time applied to it.

For example, given a span like P1dT1.5h, the unit would be Unit::Hour, the value would be 1 and the fraction would be 500_000_000. The span given would just be 1d. The span returned would be P1dT1h30m.

Note that fraction can be a fractional hour, minute, second, millisecond or microsecond (even though its type suggests its only a fraction of a second). When milliseconds or microseconds, the given fraction has any sub-nanosecond precision truncated.

Errors

This can error if the resulting units would be too large for the limits on a span. This also errors if unit is not Hour, Minute, Second, Millisecond or Microsecond.