Type Alias Signed 

pub type Signed<Extractor, Config, Digest, VerifyKey> = RequestSignature<Extractor, SignedRequest<Config, Digest, VerifyKey>>;

An alias to simplify extracting a signed request

async fn protected(_: Signed<String, (), (), Key>) -> &'static str {
    "hewwo, mr obama"
}

Aliased Type

pub struct Signed<Extractor, Config, Digest, VerifyKey> { /* private fields */ }