code: protected void endPersistence(final BufferedWriter writer) throws IOException {
          // Append any additional users to the end of the file.
          for (Object currentKey : toSave.keySet()) {
              String key = (String) currentKey;
              if (!key.contains(DISABLE_SUFFIX_KEY)) {
                  writeProperty(writer, key, null);
              }
          }
  
          toSave = null;
      }
docs: Method called to indicate persisting the properties file is now complete.
  
  @throws IOException