chore: import upstream snapshot with attribution

python/ray/serve/gang.py

@@ -0,0 +1,26 @@
+from dataclasses import dataclass
+from typing import List
+
+from ray.util.annotations import DeveloperAPI
+
+
+@DeveloperAPI
+@dataclass
+class GangContext:
+    """Context information for a replica that is part of a gang."""
+
+    gang_id: str
+    """Unique identifier for this gang."""
+
+    rank: int
+    """This replica's rank within the gang (0-indexed)."""
+
+    world_size: int
+    """Total number of replicas in this gang."""
+
+    member_replica_ids: List[str]
+    """List of replica IDs in this gang, ordered by rank."""
+
+    pg_name: str = ""
+    """Name of the gang placement group. Used to recover the PG reference
+    after controller restart and during placement group leak detection."""