Update Tornado lib

libs/tornado/platform/interface.py

@@ -39,13 +39,17 @@ class Waker(object):
     the ``IOLoop`` is closed, it closes its waker too.
     """
     def fileno(self):
-        """Returns a file descriptor for this waker.
+        """Returns the read file descriptor for this waker.
 
         Must be suitable for use with ``select()`` or equivalent on the
         local platform.
         """
         raise NotImplementedError()
 
+    def write_fileno(self):
+        """Returns the write file descriptor for this waker."""
+        raise NotImplementedError()
+
     def wake(self):
         """Triggers activity on the waker's file descriptor."""
         raise NotImplementedError()