Move stream initialization.

Author: Lukasa

hyper/http20/connection.py

@@ -373,11 +373,13 @@ def _connect_upgrade(self, sock):
         self._send_outstanding_data()
 
         # The server will also send an initial settings frame, so get it.
-        self._recv_cb()
-
+        # However, we need to make sure our stream state is set up properly
+        # first, or any extra data we receive might cause us problems.
         s = self._new_stream(local_closed=True)
         self.recent_stream = s
 
+        self._recv_cb()
+
     def _send_preamble(self):
         """
         Sends the necessary HTTP/2 preamble.