default void processChallenge(
            HttpHost host,
            boolean challenged,
            AuthChallenge authChallenge,
            HttpContext context) throws MalformedChallengeException, AuthenticationException {
        processChallenge(authChallenge, context);
    }
Processes the given auth challenge. Some authentication schemes may involve multiple
challenge-response exchanges. Such schemes must be able to maintain internal state
when dealing with sequential challenges.
<p>
When {@link #isChallengeExpected()} returns true, but no challenge was sent, this method
must be called with a null {@link AuthChallenge} so that the scheme can handle this situation.

@param host HTTP host
@param challenged true if the response was unauthorised (401/407)
@param authChallenge the auth challenge or null if no challenge was received
@param context HTTP context

@throws MalformedChallengeException in case the auth challenge is incomplete,
@throws AuthenticationException in case the authentication process is unsuccessful.

@since 5.5
httpclient5/src/main/java/org/apache/hc/client5/http/auth/AuthScheme.java