Function CFStringCreateExternalRepresentation 

pub extern "C-unwind" fn CFStringCreateExternalRepresentation(
    alloc: Option<&CFAllocator>,
    the_string: Option<&CFString>,
    encoding: CFStringEncoding,
    loss_byte: u8,
) -> Option<CFRetained<CFData>>

👎Deprecated: renamed to CFString::new_external_representation

Available on crate features CFData and CFString only.