public List<Map<String, Object>> walkRootFileNodes()
            throws IOException, TikaException, SAXException {
        List<Map<String, Object>> res = new ArrayList<>();
        if (options.isCrawlAllFileNodesFromRoot()) {
            res.add(walkFileNodeList(oneNoteDocument.root, null));
        } else {
            for (ExtendedGUID revisionListGuid : oneNoteDocument.revisionListOrder) {
                Map<String, Object> structure = new HashMap<>();
                structure.put("oneNoteType", "Revision");
                structure.put("revisionListGuid", revisionListGuid.toString());
                FileNodePtr fileNodePtr =
                        oneNoteDocument.revisionManifestLists.get(revisionListGuid);
                structure.put("fileNode", walkRevision(fileNodePtr));
                res.add(structure);
            }
        }
        return res;
    }
Walk the root file nodes, depending on the options will crawl revisions or the entire
revision tree.

@return List of the root file nodes.
@throws IOException Can throw these when manipulating the seekable byte channel.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/onenote/OneNoteTreeWalker.java