code: def ground_truth_bottleneck(C, dtype, explicit_nhwc):
      bottleneck = Bottleneck(
          C, C, C, use_cudnn=True, explicit_nhwc=explicit_nhwc
      )
      bottleneck.to(dtype=dtype, device="cuda")
      for p in bottleneck.parameters():
          torch.distributed.broadcast(p, 0)
      for b in bottleneck.buffers():
          torch.distributed.broadcast(b, 0)
      return bottleneck
  
imports: import unittest
  import torch
  from torch.testing._internal import common_utils
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 1 for calling a global function with example usage: ground_truth_bottleneck(C, dtype, explicit_nhwc) and returns: bottleneck