Represents the "SetFf" entry of the fdf field dictionary object.

It is an optional entry defined as part of the PDF 1.0 specification.

It contains an integer representing a PDF numeric object.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 246, page 461.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 249, page 559.

The SetFf integer is ORed into the target field's Ff flags, setting specific bits without affecting others. This is the preferred way to enable individual field flags from an FDF.