Represents the "StartResource" entry of the slideshow dictionary object.

It is a required entry defined as part of the PDF 1.4 specification.

It contains a string representing a PDF string object.

This string contains raw byte data. So it looks like a string but really it is just a wrapper for data.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 297, page 510.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 308, page 637.