Repaints a region of the buffer, generally called by a buffer
administrator.
(send a-wx:media-buffer refresh xywidthheightdraw-caret)->void x : inexact real y : inexact real width : inexact real height : inexact real draw-caret : small integer
The x, y, width, and height arguments specify
the area that needs repainting in buffer coordinates.
See Caret for information about draw-caret.