OptionalbaseOptionalextraIf true, this source contains extra data not bound into the /data directory Only used for source with baseURL 'ium:/'
OptionallastOptionaloptionsOptionaloriginalIf there is an originalRelativePath,
ItemData methods must use it instead of relativePath
to get the data from a distant resource.
OptionalsizeOptionaluuid
If the baseURL don't start with 'ium:/', it should be a http(s) base url. To fetch the resource, the url should be
new URL(originalRelativePath ?? relativePath, baseURL)