Comment by gwd

> This is the multi-million dollar .unwrap() story.

While there are certainly many things to admire about Rust, this is why I prefer Golang's "noisy" error handling. In golang that would be either:

    feature_values, err := features.append_with_names(...)

And the compiler would have complained that this value of `err` was unused; or you'd write:

    feature_values, _ := features.append_with_names(...)

And it would be far more obvious that an error message is being ignored.

(Renaming `unwrap` to `unwrapOrPanic` would probably help too.)