Issues with example code

[matzipan]

Hi, I'm trying the example code, and I stumbled upon this specific line.

When reproducing it, I had to add a .as_ref() to make the compiler stop complaining. Also an extra unwrap(). As so:

    let e = fetch.as_ref().unwrap().envelope().unwrap();

I don't see the CI failing. So I'm wondering if the CI never ends up running building this line of code or whether I'm doing something wrong.

I am 0.4.1.

Thanks for all the work.