public CollectionSchema.MessageFactory getEnumSetFactory()
    {
        CollectionSchema.MessageFactory enumSetFactory = this.enumSetFactory;
        if (enumSetFactory == null)
        {
            synchronized (this)
            {
                if ((enumSetFactory = this.enumSetFactory) == null)
                    this.enumSetFactory = enumSetFactory = newEnumSetFactory(this);
            }
        }
        return enumSetFactory;
    }
Returns the factory for an EnumSet (lazy).
protostuff-runtime/src/main/java/io/protostuff/runtime/EnumIO.java