int getLargestTermIndex() {
        if (emits == null || emits.isEmpty()) {
            return -1;
        }
        return largestTermIndex;
    }
points to the index of {@link AhoCorasickDoubleArrayTrie#words}
turms-plugins/turms-plugin-antispam/src/main/java/im/turms/plugin/antispam/core/ac/State.java