@Override
    public String getMechanismName() {
        return OAuthBearerLoginModule.OAUTHBEARER_MECHANISM;
    }
{@code SaslClient} implementation for SASL/OAUTHBEARER in Kafka. This
implementation requires an instance of {@code AuthenticateCallbackHandler}
that can handle an instance of {@link OAuthBearerTokenCallback} and return
the {@link OAuthBearerToken} generated by the {@code login()} event on the
{@code LoginContext}. Said handler can also optionally handle an instance of {@link SaslExtensionsCallback}
to return any extensions generated by the {@code login()} event on the {@code LoginContext}.

@see <a href="https://tools.ietf.org/html/rfc6750#section-2.1">RFC 6750,
     Section 2.1</a>
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/internals/OAuthBearerSaslClient.java