@Override
  public AppendFiles appendFile(DataFile file) {
    appendFiles.appendFile(file);
    addIcebergDataFile(file);
    return this;
  }
Implementation of {@link AppendFiles} for mixed-format table, adding tracing and watermark
generating logics.
amoro-format-iceberg/src/main/java/org/apache/amoro/op/MixedAppendFiles.java