@Override
  @Nullable
  public ByteBuffer keyMetadata() {
    if (keyMetadata == null) {
      return null;
    }
    return ByteBuffer.wrap(keyMetadata);
  }
Copy from trino-iceberg TrinoDeleteFile and do some change to adapt mixed-format table
amoro-format-mixed/amoro-mixed-trino/src/main/java/org/apache/amoro/trino/delete/TrinoDeleteFile.java