Question about rendering with drivers

[tfurrebo]

Currently I have a `driver_display_callback` to render to a view with live bucket rendering, is there any way to do this with the built-in drivers: `driver_exr`, `driver_png`, etc.?

[tfurrebo]

Or is the proper way to have two different drivers, one for saving, and one for displaying, like so:

outputs_aovs = ( str.encode(opts.aov_pass + "__deepexr"), 
		 str.encode(opts.aov_pass + "__driver"), 
		)