Create a shortcut to pause Preview viewport Cycles rendering? I'm fairly sure to create the shortcut for pausing the cycles preview render starts with wm.context_toggle, but when I put in cycles.preview_pause, an error is thrown, saying that context has no object attribute cycles.

What am I doing wrong?
If you use scene.cycles.preview_pause then it'll work. However it seems the GUI doesn't update. So when you resume the render you'll need to move the viewport momentarily before it will start rendering again. I'm not sure why this is, though.