chore: import upstream snapshot with attribution

vllm/v1/worker/cpu/buffer_utils.py

@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from collections.abc import Sequence
+
+import torch
+
+from vllm.utils.platform_utils import is_uva_available
+
+
+class UvaBuffer:
+    def __init__(self, size: int | Sequence[int], dtype: torch.dtype):
+        if not is_uva_available():
+            raise RuntimeError("UVA is not available")
+        self.cpu = torch.zeros(size, dtype=dtype, device="cpu")
+        self.np = self.cpu.numpy()
+        self.uva = self.cpu