@Override
  protected void saveEntityName(BufferedOutputStream outputStream, Role role) throws IOException {
    super.saveEntityName(outputStream, role);
    IOUtils.writeString(
        outputStream, ((User) role).getPassword(), STRING_ENCODING, encodingBufferLocal);
  }
All user/role file store in config node's user/role folder. when our system start, we load all
user/role from folder. If we did some alter query, we just store raft log.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/auth/user/LocalFileUserAccessor.java