pub fn enable(&mut self, encoding: CompressionEncoding) {
        for e in self.inner.iter_mut() {
            match e {
                Some(e) if *e == encoding => return,
                None => {
                    *e = Some(encoding);
                    return;
                }
                _ => continue,
            }
        }
    }
Enable a [`CompressionEncoding`].

Adds the new encoding to the end of the encoding list.
tonic/src/codec/compression.rs