public VerificationStateEntry maybeCreateVerificationStateEntry(long producerId, int sequence, short epoch) {
        VerificationStateEntry entry = verificationStates.computeIfAbsent(producerId, pid ->
            new VerificationStateEntry(time.milliseconds(), sequence, epoch)
        );
        entry.maybeUpdateLowestSequenceAndEpoch(sequence, epoch);
        return entry;
    }
Maybe create the VerificationStateEntry for a given producer ID and return it.
This method also updates the sequence and epoch accordingly.
storage/src/main/java/org/apache/kafka/storage/internals/log/ProducerStateManager.java