$ cargo run
   Compiling shared-state v0.1.0 (file:///projects/shared-state)
error[E0382]: borrow of moved value: `counter`
  --> src/main.rs:21:29
   |
5  |     let counter = Mutex::new(0);
   |         ------- move occurs because `counter` has type `Mutex<i32>`, which does not implement the `Copy` trait
...
8  |     for _ in 0..10 {
   |     -------------- inside of this loop
9  |         let handle = thread::spawn(move || {
   |                                    ------- value moved into closure here, in previous iteration of loop
...
21 |     println!("Result: {}", *counter.lock().unwrap());
   |                             ^^^^^^^ value borrowed here after move
   |
help: consider moving the expression out of the loop so it is only moved once
   |
8  ~     let mut value = counter.lock();
9  ~     for _ in 0..10 {
10 |         let handle = thread::spawn(move || {
11 ~             let mut num = value.unwrap();
   |

For more information about this error, try `rustc --explain E0382`.
error: could not compile `shared-state` (bin "shared-state") due to 1 previous error