TN3: XR needs a standardized in XR immersion controls

Like an on-off switch there are gradations of on and off.  There are dimmer switches, and they have ramp rates.  Entering and leaving XR should be as gradual or as rapid as one desires.  Currently it is like being buckled into a car seat.  It isn't easy to just get out.  This can be dangerous or annoying.  It should be a standardized "lever" on the experience.  

TODO: define the experience.