@Override
        public Key resolveKey(JsonWebSignature jws, List<JsonWebStructure> nestingContext) throws UnresolvableKeyException {
            return delegate.resolveKey(jws, nestingContext);
        }
<code>RefCountingVerificationKeyResolver</code> allows us to share a single
{@link CloseableVerificationKeyResolver} instance between multiple
{@link AuthenticateCallbackHandler} instances and perform the lifecycle methods the
appropriate number of times.
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/OAuthBearerValidatorCallbackHandler.java