anchor.diff:  
       (setf (cepl.streams::buffer-stream-start streamer) new-start-pos
             (cepl.streams:buffer-stream-length streamer) c-len)
  +
  +    (when draw-mode
  +      (setf (cepl.streams::buffer-stream-draw-mode streamer) draw-mode))
   
       (cepl.gpu-arrays::with-gpu-array-range-as-pointer
           (g-ptr g-arr new-start-pos c-len
  
positive.code:             (gpu-array-element-type arr)
              (first (gpu-array-dimensions arr)))))
  
  (defun make-buffer-streamer (dimensions element-type)
    (when (listp dimensions)
      (assert (= (length dimensions) 1)))
    (assert element-type)
    (let* ((len (first (ensure-list dimensions)))
           (array (make-gpu-array nil :element-type element-type
                                  :dimensions len
  
negative.code:      (%init-streamer
        (cepl.streams::init-buffer-stream-from-id
         %pre% (cepl.vaos:make-vao gpu-arrays nil)
         gpu-arrays nil 0 len t draw-mode))
       (make-uninitialized-streamer)
       gpu-arrays)))
  
  