public void add(MethodTuple tuple) {
            Set<MethodTuple> set = tuples.get(tuple.name);
            if (set == null) {
                set = new HashSet<>();
                tuples.put(tuple.name, set);
            }
            set.add(tuple);
        }
@param config  config to serialize
@param mode    serialization mode
@param writer  writer
@param charset charset
@throws Exception
tika-core/src/main/java/org/apache/tika/config/TikaConfigSerializer.java