$ cargo run
   Compiling shared-state v0.1.0 (file:///projects/shared-state)
error[E0277]: `std::rc::Rc<std::sync::Mutex<i32>>` cannot be sent between threads safely
   --> src/main.rs:11:22
    |
11  |         let handle = thread::spawn(move || {
    |                      ^^^^^^^^^^^^^ `std::rc::Rc<std::sync::Mutex<i32>>` cannot be sent between threads safely
    |
    = help: within `[closure@src/main.rs:11:36: 15:10 counter:std::rc::Rc<std::sync::Mutex<i32>>]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::sync::Mutex<i32>>`
    = note: required because it appears within the type `[closure@src/main.rs:11:36: 15:10 counter:std::rc::Rc<std::sync::Mutex<i32>>]`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: could not compile `shared-state`.

To learn more, run the command again with --verbose.
