This value can be null.
If this property is not null then the cell uses the given view as the accessory (for the normal state). The value of the UITableViewCell.Accessory is ignored when AccessoryView is set. The custom accessory view can be a control, a label or a custom view.
The accessory view cross-fades between normal and editing states if it is set for both states; use the UITableViewCell.EditingAccessoryView property to set a custom accessory view to be displayed in editing mode. If an accessory is not defined for both states (normal and editing) the the accessory view is animated to slide in or out, as required.