Unwrap of a None value when config is not set

[mibes]

In version 0.4.0 there is a panic when call is called when an unset config:

tokio-runtime-worker' panicked at 'called `Option::unwrap()` on a `None` value', /Users/mibes/.cargo/registry/src/github.com-1ecc6299db9ec823/hyper-alpn-0.4.0/src/lib.rs:263:22
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

This is due to the wrong config-clone that is used after self.build_config(). I suppose it should have gotten the config from self:

let config = self.config.clone();
if config.is_none() {
    self.build_config()
}
let config = config.unwrap();

I'll do a pull request to address this.

[vhawley]

I am experiencing this issue too.

The fix in the linked pull request looks and behaves as expected.