Balanced concurrency

room_cal/service_api/_airbnb.py

@@ -324,7 +324,7 @@ class _AirbnbClient:
       dt = datetime.fromisoformat(ts.replace('Z', '+00:00'))
       return dt.astimezone(ZoneInfo(self._tz)).date().isoformat()
 
-    _sem = asyncio.Semaphore(15)
+    _sem = asyncio.Semaphore(10)
 
     async def fetch_details(c: str) -> tuple[str, str | None, str | None, str | None, str | None, str | None]:
       async with _sem: