deinit

pub fn deinit(self: *Cache, gpa: std.mem.Allocator, backend: Backend) void {
        defer self.* = undefined;
        var it = self.cache.iterator();
        while (it.next()) |item| {
            item.value_ptr.deinit(gpa, backend);
        }
        self.cache.deinit(gpa);

        for (self.database.items) |*source| {
            if (source.allocator) |a| {
                a.free(source.bytes);
            }
        }
        self.database.deinit(gpa);
    }