code: def get_object_data(self, ref):
          
          hexsha, typename, size, stream = self.stream_object_data(ref)
          data = stream.read(size)
          del(stream)
          return (hexsha, typename, size, data)
docs: As get_object_header, but returns object data as well
          :return: (hexsha, type_string, size_as_int,data_string)
          :note: not threadsafe