pub fn check(self) -> Result<(), TokenStream> {
            let errors = self.errors.borrow_mut().take().unwrap();
            match errors.len() {
                0 => Ok(()),
                _ => Err(to_compile_errors(errors)),
            }
        }
Consume this object, producing a formatted error string if there are
errors.
esp-hal-procmacros/src/embassy.rs