$ cargo check
    Checking hello v0.1.0 (file:///projects/hello)
error[E0599]: no function or associated item named `new` found for type `hello::ThreadPool` in the current scope
  --> src/bin/main.rs:11:28
   |
11 |     let pool = ThreadPool::new(4);
   |                            ^^^ function or associated item not found in `hello::ThreadPool`

error: aborting due to previous error

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

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