Function spawn 

pub unsafe extern "C" fn spawn(
    id: *mut Tid,
    func: extern "C" fn(usize),
    arg: usize,
    prio: u8,
    core_id: isize,
) -> i32

spawn a new thread

spawn() starts a new thread. The new thread starts execution by invoking func(usize); arg is passed as the argument to func. prio defines the priority of the new thread, which can be between LOW_PRIO and HIGH_PRIO. core_id defines the core, where the thread is located. A negative value give the operating system the possibility to select the core by its own.