Remove __enter__ and __exit__ from MemorySnapshotProfiler (pytorch#611)

Summary:

There is no need for MemorySnapshotProfiler to be a context manager since it conflicts with start_step and stop_step

Differential Revision: D51049497

torchtnt/utils/memory_snapshot_profiler.py

@@ -6,8 +6,7 @@
 
 import logging
 from dataclasses import dataclass
-from types import TracebackType
-from typing import Optional, Type
+from typing import Optional
 
 import torch
 from torchtnt.utils.oom import attach_oom_observer, log_memory_snapshot
@@ -115,17 +114,6 @@ def __init__(
             f"Created MemorySnapshotProfiler with MemorySnapshotParams={self.params}."
         )
 
-    def __enter__(self) -> None:
-        self.start()
-
-    def __exit__(
-        self,
-        exc_type: Optional[Type[BaseException]],
-        exc_value: Optional[BaseException],
-        tb: Optional[TracebackType],
-    ) -> Optional[bool]:
-        self.stop()
-
     def start(self) -> None:
         if not torch.cuda.is_available():
             logger.warn("CUDA unavailable. Not recording memory history.")