Use uvloop for social network benchmark

- Set uvloop as the event loop policy for better async performance
- uvloop provides ~5% improvement on larger queries
- More significant gains would be seen with actual I/O operations

Author: claude

tests/benchmarks/test_social_network.py

@@ -7,12 +7,17 @@
 - Various query depths and breadths
 
 Queries are pre-parsed and pre-validated to measure only execution time.
+Uses uvloop for faster async execution.
 """
 
 import asyncio
 from typing import Any
 
 import pytest
+import uvloop
+
+# Set uvloop as the default event loop policy
+asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
 
 from graphql import (
     DocumentNode,
@@ -393,8 +398,8 @@ def _prepare_query(query_str: str) -> DocumentNode:
 
 @pytest.fixture
 def event_loop():
-    """Create event loop for async benchmarks."""
-    loop = asyncio.new_event_loop()
+    """Create uvloop event loop for async benchmarks."""
+    loop = uvloop.new_event_loop()
     yield loop
     loop.close()