private synchronized void recordTickThreadStage(String description) {
        assert description != null;

        log.trace("Recording new tick thread stage: {}", description);

        // Preserve the current stage to report to requests submitted after this method is invoked
        this.tickThreadStage = new Stage(description, time.milliseconds());
        // Report the current stage to all pending requests
        requests.forEach(request -> request.callback().recordStage(tickThreadStage));
        // And, if there is an in-progress request, report the stage to it as well
        Optional.ofNullable(currentRequest).map(DistributedHerderRequest::callback)
                .ifPresent(callback -> callback.recordStage(tickThreadStage));
    }
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