How does an elevator offload function works in fly by wire flight control systems? In some fly by wire systems I found that there is no trim in the traditional sense. I believe it is because the forces that pilot feels on the stick are artificial. I was told that those fly by wire systems has elevator offload functionality that moves H-stab.


Can anyone explain how elevator offload functionality is implemented?
Does the artificial feel system generate force in response to airspeed and vertical acceleration? (like making pilot push harder for every knot/every G away from the trimmed state?)
Is trimming necessary for FBW systems and if so How does the fly by wire system implements the trim?
Regarding the first point, from Lufthansa Technical Training Manual for 777, page 30:


  Elevator Offload Function
  Operates only in the AirCommands to Determine when the Elevator is not at the Neutral Position for more than two seconds minimum.Commands the Horizontal Stabilizer to move as a Function of Airspeed. The Movement of the Horizontal Stabilizer then causes the Elevator to move to the Neutral Position