class_docstr: Lazily serves tensor to request device. This class extends
  _MultiDeviceReplicator to allow support for "cpu" as a device.
code: def __init__(self, master_tensor: torch.Tensor) -> None:
      assert _is_supported_device(master_tensor)
      self.master = master_tensor
      self._per_device_tensors: Dict[torch.device, torch.Tensor] = {}
  
imports: import logging
  from collections import abc, defaultdict
  from typing import Any, Dict, Iterable, List, Optional, overload, Sequence, Tuple, Union
  import torch
  import torch.distributed
  from torch.cuda.amp.grad_scaler import _MultiDeviceReplicator, GradScaler, OptState
  from torch.distributed.distributed_c10d import ProcessGroup
label_desc: Use image node_id 1 to create a new _GeneralMultiDeviceReplicator object from inherited base classes: _MultiDeviceReplicator with example: obj = _GeneralMultiDeviceReplicator(master_tensor)