Sets which stereo buffers should be drawn to.
The default is cogl_stereo_both, which means that both the left and right buffers will be affected by drawing. For this to have an effect, the display system must support stereo drawables, and the framebuffer must have been created with stereo enabled. (See set_stereo_enabled, get_is_stereo.)
a pointer to a Framebuffer
A StereoMode specifying which stereo buffers should be drawn tow.