public const unowned string THUMBNAIL_IS_VALID
A key in the "thumbnail" namespace for checking whether the thumbnail is outdated.
This attribute is true if the thumbnail is up-to-date with the file it represents, and false if the file has been modified since the thumbnail was generated.
If g_file_attribute_thumbnailing_failed is true and this attribute is false, it indicates that thumbnailing may be attempted again and may succeed.
Corresponding FileAttributeType is g_file_attribute_type_boolean.