To connect a request/response system to a log-oriented system such as presented here, an option is to use the request/reply server as a proxy for the log-oriented one :

  - producing the requests to the log-oriented system,

  - consuming the responses at some endpoint/topic of the dataflow,

  - linking responses to requests using some id propagated along the whole dataflow,

  - dealing with a cache of pending requests, asynchronous responses and timeout

In practice, to keep things manageable - latency and count of pending connections, we can't always wait for the very end of the request processing dataflow; but we can at least choose an intermediate log/topic where progress is sufficient to forge a response or to reply with 202 accepted request.