As get_object_header, but returns the data as a stream
		:return: (hexsha, type_string, size_as_int, stream)
		:note: This method is not threadsafe, you need one independent	Command instance
			per thread to be safe !

def stream_object_data(self, ref):
		"""As get_object_header, but returns the data as a stream
		:return: (hexsha, type_string, size_as_int, stream)
		:note: This method is not threadsafe, you need one independent	Command instance
			per thread to be safe !"""
		cmd = self.__get_persistent_cmd("cat_file_all", "cat_file", batch=True)
		hexsha, typename, size = self.__get_object_header(cmd, ref)
		return (hexsha, typename, size, self.CatFileContentStream(size, cmd.stdout))