pub fn new_not_signing<D>(dispatcher: D) -> Self
    where
        D: DispatchSignedRequest + Send + Sync + 'static,
    {
        let inner = ClientInner::<StaticProvider, D> {
            credentials_provider: None,
            dispatcher: Arc::new(dispatcher),
            content_encoding: Default::default(),
        };
        Client {
            inner: Arc::new(inner),
        }
    }
Create a client from a request dispatcher without a credentials provider. The client will
neither fetch any default credentials nor sign any requests. A non-signing client can be
useful for calling APIs like `Sts::assume_role_with_web_identity` and
`Sts::assume_role_with_saml` which do not require any request signing or when calling
AWS compatible third party API endpoints which employ different authentication mechanisms.
rusoto/core/src/client.rs