docs: protected ParsableBox createMfra(Movie movie, Container isoFile) {
          MovieFragmentRandomAccessBox mfra = new MovieFragmentRandomAccessBox();
          for (Track track : movie.getTracks()) {
              mfra.addBox(createTfra(track, isoFile));
          }
  
          MovieFragmentRandomAccessOffsetBox mfro = new MovieFragmentRandomAccessOffsetBox();
          mfra.addBox(mfro);
          mfro.setMfraSize(mfra.getSize());
          return mfra;
      }