code: public SerDeserializers register(Class<?> type, SerDeserializer deserializer) {
          deserializers.put(type, deserializer);
          return this;
      }
docs: Adds the deserializer to be used for the specified type.
  
  @param type  the type, not null
  @param deserializer  the deserializer, not null
  @return this, for chaining, not null