fix Sync hook used as async hook

Signed-off-by: Shi, Stone <[email protected]>

Author: shijiadong2022

Diff for: instrumentation/opentelemetry-instrumentation-httpx/src/opentelemetry/instrumentation/httpx/__init__.py

@@ -731,7 +731,9 @@ def _instrument(self, **kwargs):
         self._original_async_client = httpx.AsyncClient
         request_hook = kwargs.get("request_hook")
         response_hook = kwargs.get("response_hook")
-        async_request_hook = kwargs.get("async_request_hook", request_hook)
+        async_request_hook = kwargs.get(
+            "async_request_hook", self._wrap_async_request_hook(request_hook)
+        )
         async_response_hook = kwargs.get("async_response_hook", response_hook)
         if callable(request_hook):
             _InstrumentedClient._request_hook = request_hook
@@ -749,6 +751,16 @@ def _instrument(self, **kwargs):
         httpx.Client = httpx._api.Client = _InstrumentedClient
         httpx.AsyncClient = _InstrumentedAsyncClient
 
+    # Wrap a given request hook function and ensure it is asynchronous
+    def _wrap_async_request_hook(self, request_hook_func):
+        if request_hook_func is None:
+            return None
+
+        async def async_request_hook(span, req):
+            return request_hook_func(span, req)
+
+        return async_request_hook
+
     def _uninstrument(self, **kwargs):
         httpx.Client = httpx._api.Client = self._original_client
         httpx.AsyncClient = self._original_async_client