Function keyed_assignment_items 

pub fn keyed_assignment_items<D, K, P, S, const N: usize>(
    assignment: &KeyedRosterAssignment<D, K, P, S, N>,
    row: impl FnMut(usize, &K, &D, &S, &P) -> Result<Vec<GeneratedToken>, Overflow>,
) -> Result<Vec<GeneratedToken>, GeneratedRowRefusal>

Projects one exact keyed assignment into a flat item run in denominator order.

The caller supplies every row’s complete tokens and remains responsible for the meaning of each item.

Errors

Returns the first GeneratedRowRefusal where a callback refuses, emits no token, or emits more than the generated-token magnitude.