Function try_peek_next_hold 

pub fn try_peek_next_hold<M: Memory + Copy>(
    m: M,
    queue: u64,
    cursor: &mut Cursor,
) -> (i32, u64)

Hold the next task in deadline order after cursor and advance it, so that a bounded scan can resume even after the tasks it passed have left. Returns 0 with no task at the end, EBUSY when contended.