Function IOConnectCallScalarMethod 

pub unsafe extern "C-unwind" fn IOConnectCallScalarMethod(
    connection: mach_port_t,
    selector: u32,
    input: *const u64,
    input_cnt: u32,
    output: *mut u64,
    output_cnt: *mut u32,
) -> kern_return_t

Available on crate feature libc only.