handleExchange
Handles a single message exchange.
Implementations should process the message exchange, perform any necessary business logic, and return a Mono that completes when processing is finished. The exchange may be acknowledged or additional processing may occur.
This method is called for each message exchange in the processing pipeline. Implementations should be idempotent and handle errors appropriately.
Return
A Mono that completes when the exchange is handled. The Mono may emit errors for failed processing.
Parameters
exchange
The message exchange to handle