In this instance I'd normally take the lane maintaining a position such that a car cannot pass without a lane change. I do this so a drive won't think he can squeeze by when there another car to his left.
However, if traffic is heavy on a longish stretch, and I feel I'm causing a backup, I'll move over once the car behind has slowed to my speed, allowing him to squeeze by. I'll maintain that right edge position as long as drivers are slowing and passing at not much over my speed.
In considering my approach, understand that I'm from NYC and very used to close passes, but not fast close passes.