cl-stream/utf8-stream

diff --git a/babel-output-stream.lisp b/babel-output-stream.lisp
index bd64ec1..88c8be3 100644
--- a/babel-output-stream.lisp
+++ b/babel-output-stream.lisp
@@ -30,6 +30,9 @@
 (defmethod stream-flush-output ((stream babel-output-stream))
   (stream-flush-output (stream-underlying-stream stream)))
 
+(defmethod stream-open-p ((stream babel-output-stream))
+  (stream-open-p (stream-underlying-stream stream)))
+
 (defmethod stream-write ((stream babel-output-stream) (element fixnum))
   (assert (typep element '(unsigned-byte 8)))
   (write (stream-underlying-stream stream) element))