$ cargo check
    Checking hello v0.1.0 (file:///projects/hello)
error[E0599]: no method named `join` found for enum `Option` in the current scope
  --> src/lib.rs:52:27
   |
52 |             worker.thread.join().unwrap();
   |                           ^^^^ method not found in `Option<JoinHandle<()>>`
   |
note: the method `join` exists on the type `JoinHandle<()>`
  --> /rustc/9b00956e56009bab2aa15d7bff10916599e3d6d6/library/std/src/thread/mod.rs:1657:5
help: consider using `Option::expect` to unwrap the `JoinHandle<()>` value, panicking if the value is an `Option::None`
   |
52 |             worker.thread.expect("REASON").join().unwrap();
   |                          +++++++++++++++++

error[E0308]: mismatched types
  --> src/lib.rs:72:22
   |
72 |         Worker { id, thread }
   |                      ^^^^^^ expected `Option<JoinHandle<()>>`, found `JoinHandle<_>`
   |
   = note: expected enum `Option<JoinHandle<()>>`
            found struct `JoinHandle<_>`
help: try wrapping the expression in `Some`
   |
72 |         Worker { id, thread: Some(thread) }
   |                      +++++++++++++      +

Some errors have detailed explanations: E0308, E0599.
For more information about an error, try `rustc --explain E0308`.
error: could not compile `hello` (lib) due to 2 previous errors