Allow render to access status code (#938)

* Allow render to access status code

Minor change the sequence for init status and body, so render can access status code

* Move render before ini_headers

starlette/responses.py

@@ -42,11 +42,11 @@ def __init__(
         media_type: str = None,
         background: BackgroundTask = None,
     ) -> None:
-        self.body = self.render(content)
         self.status_code = status_code
         if media_type is not None:
             self.media_type = media_type
         self.background = background
+        self.body = self.render(content)
         self.init_headers(headers)
 
     def render(self, content: typing.Any) -> bytes: