A fragment of text as it appears in a document.
Each TextFragment spans a part of a PDF stream drawing operator.
The part may be the entire of the text drawn by the operator or it
may be a section of the text within that operator.
For example the PDF text drawing operator "(Once upon a time)
Tj" draws that text. If you search for the word "upon" the
TextFragment which is returned will reference the complete operator
via the StreamOffset
properties but properties like the Text and Rect will span only the word "upon"
within that operator.