@SuppressWarnings("unchecked")
    public <V> V getExtraOption(java.lang.String key)
    {
        return (V) extraOptions.get(key);
    }
Disabled by default (the earlier protoc 2.x versions enabled this by default, but was changed later on).
protostuff-parser/src/main/java/io/protostuff/parser/EnumGroup.java