Initial orjson support (#72754)

homeassistant/helpers/aiohttp_client.py

@@ -14,6 +14,7 @@ from aiohttp import web
 from aiohttp.hdrs import CONTENT_TYPE, USER_AGENT
 from aiohttp.web_exceptions import HTTPBadGateway, HTTPGatewayTimeout
 import async_timeout
+import orjson
 
 from homeassistant import config_entries
 from homeassistant.const import EVENT_HOMEASSISTANT_CLOSE, __version__
@@ -97,6 +98,7 @@ def _async_create_clientsession(
     """Create a new ClientSession with kwargs, i.e. for cookies."""
     clientsession = aiohttp.ClientSession(
         connector=_async_get_connector(hass, verify_ssl),
+        json_serialize=lambda x: orjson.dumps(x).decode("utf-8"),
         **kwargs,
     )
     # Prevent packages accidentally overriding our default headers