anchor.diff:  
   (declaim (inline check-if-open check-if-accepts-octets
             check-if-accepts-characters stream-accepts-characters?
  -          stream-accepts-octets? vector-extend))
  +          stream-accepts-octets? vector-extend extend-vector-output-stream-buffer))
  +
  +;;; Some utilities (on top due to inlining)
  +
  +(defun vector-extend (extension vector &key (start 0) (end (length extension)))
  +  ;; copied over from cl-quasi-quote
  +  (declare (optimize speed)
  +           (type vector extension vector)
  +           (type array-index start end))
  +  (let* ((original-length (length vector))
  +         (extension-length (- end start))
  +         (new-length (+ original-length extension-length))
  +         (original-dimension (array-dimension vector 0)))
  +    (when (< original-dimension new-length)
  +      (setf vector (adjust-array vector (max (* 2 original-dimension) new-length))))
  +    (setf (fill-pointer vector) new-length)
  +    (replace vector extension :start1 original-length :start2 start :end2 end)
  +    vector))
   
   (defclass in-memory-stream (trivial-gray-stream-mixin)
     ((element-type :initform :default ; which means bivalent
  
positive.code:   (incf (vector-stream-index stream))
    byte)
  
  (defmethod stream-write-char ((stream vector-output-stream) char)
    (declare (optimize speed))
    (check-if-open stream)
  
negative.code:            (assert (stream-accepts-characters? stream))
             (extend-vector-output-stream-buffer sequence stream :start start :end end))))
      ((vector (unsigned-byte 8))
       ;; specialized branch to help inlining
       (check-if-accepts-octets stream)
       (extend-vector-output-stream-buffer sequence stream :start start :end end))
      (vector
       (check-if-accepts-octets stream)
       (extend-vector-output-stream-buffer sequence stream :start start :end end)))
    sequence)
  