Function unadjusted_boundaries 

fn unadjusted_boundaries(
    effective: NaiveDate,
    termination: NaiveDate,
    frequency: Period,
    calendar: &dyn Calendar,
    roll: RollConvention,
    stub: StubPeriodType,
    end_of_month: bool,
    is_cds: bool,
) -> Vec<NaiveDate>

The unadjusted boundaries from effective to termination: the regular periods measured from one fixed anchor in the direction stub names, the interior roll applied to each before the stop test. Schedule::generate’s core, shared with Schedule::generate_with_stubs.