Document Info dictionary metadata — a PDF's classic /Info fields.
Every field is optional and defaults to nil; a document with no /Info
dictionary yields a struct with all fields nil. Obtain it with
PdfElixide.Document.metadata/1.
For richer, XML-based metadata (which many modern PDFs carry instead of, or in
addition to, the Info dictionary) see PdfElixide.Document.xmp_metadata/1.
Fields
:title,:author,:subject— document title, author, and subject.:keywords— the raw/Keywordsstring (PDF stores it as a single string; the split list, when available, is on the XMP:subjectsfield).:creator— the application that created the original document.:producer— the application that produced the PDF.:creation_date,:mod_date— the raw PDF date strings (e.g."D:20230101120000+00'00'"); not parsed intoDateTime.:trapped— the/Trappedvalue ("True","False", or"Unknown").