// Encodes the `tfl.metadata` dictionary attribute of the module to the
  // metadata section in the final model.
  std::optional<VectorBufferOffset<BufferOffset<tflite::Metadata>>>
  CreateMetadataVector();

  // Builds and returns list of tfl.SignatureDef sections in the model.
  std::optional<VectorBufferOffset<BufferOffset<tflite::SignatureDef>>>