code: def metadata_to_buffers(metadata):
      
      results = []
  
      for key, value in metadata.items():
          assert len(key) < 256
          assert len(value) < 2 ** 32
          results.extend([
              struct.pack('!B', len(key)),
              key,
              struct.pack('!I', len(value)),
              value,
          ])
  
      return results
docs: Transform a dict of metadata into a sequence of buffers.
  
      :param metadata: The metadata, as a dict.
      :returns: A list of buffers.