@Override
    public <K, V> void forward(final K key, final V value, final To to) {
        if (!currentNode().children().isEmpty()) {
            throw new IllegalStateException("This method should only be called on 'GlobalStateStore.flush' that should not have any children.");
        }
    }
No-op. This should only be called on GlobalStateStore#flush and there should be no child nodes
streams/src/main/java/org/apache/kafka/streams/processor/internals/GlobalProcessorContextImpl.java