docs: public Entry addEntry(final Entry entry) throws Exception {
          synchronized (FileStore.getFileStore()) {
              final Feed f = getFeedDocument();
  
              final String fsid = FileStore.getFileStore().getNextId();
              updateTimestamps(entry);
  
              // Save entry to file
              final String entryPath = getEntryPath(fsid);
  
              final OutputStream os = FileStore.getFileStore().getFileOutputStream(entryPath);
              updateEntryAppLinks(entry, fsid, true);
              Atom10Generator.serializeEntry(entry, new OutputStreamWriter(os, "UTF-8"));
              os.flush();
              os.close();
  
              // Update feed file
              updateEntryAppLinks(entry, fsid, false);
              updateFeedDocumentWithNewEntry(f, entry);
  
              return entry;
          }
      }