Function dr_unregister_nudge_event 

pub unsafe extern "C" fn dr_unregister_nudge_event(
    func: Option<unsafe extern "C" fn(drcontext: *mut c_void, argument: uint64)>,
    id: client_id_t,
) -> bool_

Unregister a callback function for the nudge event. \return true if unregistration is successful and false if it is not (e.g., \p func was not registered).