Kafka streams branching and merging one of the branches back into the stream before branching? - apache-kafka-streams

Question

Is it possible to have a topology that does the following (simplified example):
/ --> branch1 --> output sink
/
(success)
/
source ---> stream ---> /
^ \
| \
| (failure)
| \
| \ --> branch2 --> retry processor -->|
| |
\--< merge back if successful after x attempts <--/
Basically the predicate that decides whether events go to the output sink is an external call which might fail, if it fails we send the event to a default branch (branch 2) where a retry processor will retry it a couple of times and if the call is successful we forward the event and merge the resulting stream back into the initial stream so that it has a chance to go to the output topic.
Is there a way to make this work? I've managed to make it go all the way to the retry processor, which does it's job and forwards the event once it is successful. But I haven't been able to make the event go back to the initial stream.
I apply a merge operation on the resulting Kstream from the retry processor with the original stream.
Example code:
KStream<String, String> stream = builder.stream("input-topic", Consumed.with(Serdes.String(), Serdes.String()));
var branches = stream.split(Named.as("type"))
.branch((key, value) -> {
try {
return someOperationThatMightFail();
} catch (Exception e) {
return false;
}
}, Branched.withFunction(kstream -> kstream,"branch1"))
.defaultBranch(Branched.withFunction(kstream -> kstream,"branch2"));
var successBranch = branches.get("branch1");
var failedBranch = branches.get("branch2");
successBranch.to("output-topic");
failedBranch.transform(retrySupplier, Named.as("retry")).merge(stream);
The other option would be to merge it with the successful branch1 after the retry processor, but I also can't seem to make that work.