Sync from v0.13

vllm/logging_utils/lazy.py

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from collections.abc import Callable
+from typing import Any
+
+
+class lazy:
+    """Wrap a zero-argument callable evaluated only during log formatting."""
+
+    __slots__ = ("_factory",)
+
+    def __init__(self, factory: Callable[[], Any]) -> None:
+        self._factory = factory
+
+    def __str__(self) -> str:
+        return str(self._factory())
+
+    def __repr__(self) -> str:
+        return str(self)