Function generate_with_start 

pub fn generate_with_start<'g>(
    rows: RowFlow<'g>,
    start: Option<Start>,
    sort: Sort,
    reverse: bool,
) -> RowFlow<'g>

Skip rows until the start bound is reached, then pass the rest (generateWithStart, memory-source.ts:653). Uses the connection comparator (reverse-aware). start = None ⇒ pass-through.