17: My Solution requires mut tx.

[cldershem]

The borrow checker does not seem happy as is.

error[E0596]: cannot borrow immutable local variable `rx` as mutable
  --> src/main.rs:30:21
   |
27 |     let Serial { tx, rx } = Serial::new().unwrap();
   |                      -- consider changing this to `mut rx`
...
30 |     let mut bytes = rx.bytes();
   |                     ^^ cannot borrow mutably

error[E0596]: cannot borrow immutable local variable `tx` as mutable
  --> src/main.rs:45:13
   |
27 |     let Serial { tx, rx } = Serial::new().unwrap();
   |                  -- consider changing this to `mut tx`
...
45 |             tx.write(byte).wait();
   |             ^^ cannot borrow mutably
error: aborting due to 2 previous errors
error: Could not compile `async`.
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