Fix typo from commit 2b44fac

Closes #169.

diff --git a/tornado/iostream.py b/tornado/iostream.py
index 4f321d5570050ea561fa482a3c2960ac8c7a4206..3bea7e12198c78f6c0e8ba7ee75307c94435bd57 100644 (file)
--- a/tornado/iostream.py
+++ b/tornado/iostream.py
@@ -359,7 +359,7 @@ class IOStream(object):
             raise IOError("Stream is closed")
 
     def _add_io_state(self, state):
-        if socket is None:
+        if self.socket is None:
             # connection has been closed, so there can be no future events
             return
         if not self._state & state: