The XRef entry describes an object slot in a XRef.
The XRef allows random access to the objects in the PDF file.
A XRef section is the part of a pdf document starting with a "xref" token.
A XRef section consists of at least one subsection.
A simple xref rebuilding parser.
The parser reads lines in the document and looks if the line begins with a object definition, which looks like: number number "obj".