$ cargo check
    Checking hello v0.1.0 (file:///projects/hello)
error[E0599]: no method named `execute` found for struct `ThreadPool` in the current scope
  --> src/bin/main.rs:16:14
   |
16 |         pool.execute(|| {
   |              ^^^^^^^ method not found in `ThreadPool`

For more information about this error, try `rustc --explain E0599`.
error: could not compile `hello` due to previous error