private UriBuilder namespacedUrl(String workerUrl) {
        UriBuilder result = UriBuilder.fromUri(workerUrl);
        for (String namespacePath : restNamespace) {
            result = result.path(namespacePath);
        }
        return result;
    }
Checks a given {@link InternalRequestSignature request signature} for validity and adds an exception
to the given {@link Callback} if any errors are found.

@param requestSignature the request signature to validate
@param callback callback to report invalid signature errors to
@return true if the signature was not valid
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java