@TestOnly
  public void writeInComplete(Modification mod) throws IOException {
    if (fos == null) {
      fos = new FileOutputStream(filePath, true);
    }
    String line = encodeModification(mod);
    if (line != null) {
      fos.write(line.substring(0, 2).getBytes());
      force();
    }
  }
Construct a LocalTextModificationAccessor using a file specified by filePath.

@param filePath the path of the file that is used for storing modifications.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/modification/v1/io/LocalTextModificationAccessor.java