getSlotByIndex

        fn getSlotByIndex(self: *Self, entry_index: usize, ctx: ByIndexContext, header: *IndexHeader, comptime I: type, indexes: []Index(I)) usize {
            const slice = self.entries.slice();
            const h = if (store_hash) slice.items(.hash)[entry_index] else checkedHash(ctx, slice.items(.key)[entry_index]);
            const start_index = safeTruncate(usize, h);
            const end_index = start_index +% indexes.len;

            var index = start_index;
            var distance_from_start_index: I = 0;
            while (index != end_index) : ({
                index +%= 1;
                distance_from_start_index += 1;
            }) {
                const slot = header.constrainIndex(index);
                const slot_data = indexes[slot];

                // This is the fundamental property of the array hash map index.  If this
                // assert fails, it probably means that the entry was not in the index.
                assert(!slot_data.isEmpty());
                assert(slot_data.distance_from_start_index >= distance_from_start_index);

                if (slot_data.entry_index == entry_index) {
                    return slot;
                }
            }
            unreachable;
        }