@Override
    public int getCurrentPageNo() {
        return pageIndex + 1;
    }
we need to override this because we are overriding {@link #processPages(PDPageTree)}

@return
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-pdf-module/src/main/java/org/apache/tika/parser/pdf/AbstractPDF2XHTML.java