Function is_strict_prefix

server/src/server/prefix_cache.cpp:145–150

        // matching decides every restore, so that costs at most a snapshot
        // taken at a less useful place.
        while (true) {
            const auto [idx, len] =
                find_first_seq_any(ids, markers.next_role_starts, cursor);
            if (idx < 0) break;
            cursor = idx + len;
            out.push_back(cursor);
        }
        return out;
    }