so what's the "cost in complexity" here? the complexity would be there whether you went with a a hand-rolled or "zero-cost" version (at least that's the idea),

so what's the "cost in complexity" here? the complexity would be there whether you went with a a hand-rolled or "zero-cost" version (at least that's the idea), except the "zero-cost" version should require less code and thus be easier to maintain.