objc2_core_foundation

Function CFRunLoopObserverCreateWithHandler

Source 
pub unsafe extern "C-unwind" fn CFRunLoopObserverCreateWithHandler(
    allocator: Option<&CFAllocator>,
    activities: CFOptionFlags,
    repeats: bool,
    order: CFIndex,
    block: Option<&Block<dyn Fn(*mut CFRunLoopObserver, CFRunLoopActivity)>>,
) -> Option<CFRetained<CFRunLoopObserver>>
Available on crate features CFBase and CFRunLoop and block2 only.