Why Is C Faster Than Java (2009)(marc.info)

    use std::{time::Duration, ops::{DerefMut, Deref}};
    
    struct SendWrapper<T>(*mut T);
    
    impl<T> Deref for SendWrapper<T> {
        type Target = T;
    
        fn deref(&self) -> &Self::Target {
            unsafe { self.0.as_ref() }.unwrap()
        }
    }
    impl<T> DerefMut for SendWrapper<T> {
        fn deref_mut(&mut self) -> &mut Self::Target {
            unsafe { self.0.as_mut() }.unwrap()
        }
    }
    
    unsafe impl<T> Send for SendWrapper<T> {}
    
    fn main() {
        let mut x = 10;
        let p1: *mut usize = &mut x;
        let p2: *mut usize = &mut x;
        let mut s1 = SendWrapper(p1);
        let mut s2 = SendWrapper(p2);
    
        let j1 = std::thread::spawn(move || {
            *s1.deref_mut() += 1;
        });
        let j2 = std::thread::spawn(move ||  {
            std::thread::sleep(Duration::from_secs(1));
            *s2.deref_mut() += 1;
        });
        j1.join().unwrap();
        j2.join().unwrap();
        println!("x: {}", x);
    }