Maps a worker subtype string (lowercased /Subtype) to a PdfAnnotationSubtype, falling back to unknown for anything not surfaced (widgets, popups, and rarer types).
/Subtype
unknown
The name to look up.
The resulting PdfAnnotationSubtype.
Maps a worker subtype string (lowercased
/Subtype) to a PdfAnnotationSubtype, falling back tounknownfor anything not surfaced (widgets, popups, and rarer types).