def PerformSlicedDownload(self, object_name, file_name, serialization_data):
    if file_name:
      with open(file_name, 'ab') as fp:
        fp.truncate(self.thru_filesize)
    component_size = DivideAndCeil(self.thru_filesize, self.num_slices)
    args = []
    for i in range(self.num_slices):
      start_byte = i * component_size
      end_byte = min((i + 1) * (component_size) - 1, self.thru_filesize - 1)
      args.append(SliceDownloadTuple(object_name, file_name, serialization_data,
                                     start_byte, end_byte))
    self.Apply(_DownloadSlice, args, _PerfdiagExceptionHandler,
               ('total_requests', 'request_errors'),
               arg_checker=DummyArgChecker, parallel_operations_override=True,
               process_count=self.processes, thread_count=self.threads)
L{hosts.Resolver.lookupIPV6Address} returns a L{Deferred} which fires
dataset/ETHPy150Open GoogleCloudPlatform/gsutil/gslib/commands/perfdiag.py/PerfDiagCommand.PerformSlicedDownload--crossover with--dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/names/test/test_hosts.py/HostsTestCase.test_lookupIPV6Address