Function CFNotificationCenterAddObserver 

pub unsafe extern "C-unwind" fn CFNotificationCenterAddObserver(
    center: &CFNotificationCenter,
    observer: *const c_void,
    call_back: CFNotificationCallback,
    name: Option<&CFString>,
    object: *const c_void,
    suspension_behavior: CFNotificationSuspensionBehavior,
)

👎Deprecated: renamed to CFNotificationCenter::add_observer

Available on crate features CFDictionary and CFNotificationCenter only.