@defer.inlineCallbacks
    def __flush_buffer(self):
        yield self.__flush_data(self._buffer.getvalue())
        self._buffer.close()
        self._buffer = StringIO()
Returns a blob of receipt data to be used when this subscription is
dataset/ETHPy150Open twisted/txmongo/txmongo/_gridfs/grid_file.py/GridIn.__flush_buffer--crossover with--dataset/ETHPy150Open viewfinderco/viewfinder/backend/services/itunes_store.py/VerifyResponse.GetRenewalData