code: func OptFieldTypeSet(cacheType CacheType, cacheSize int) FieldOption {
  	return func(options *FieldOptions) {
  		options.fieldType = FieldTypeSet
  		options.cacheType = cacheType
  		options.cacheSize = cacheSize
  	}
  }
docs: // OptFieldTypeSet adds a set field.
  // Specify CacheTypeDefault for the default cache type.
  // Specify CacheSizeDefault for the default cache size.