stopGracefully
Performs a graceful shutdown of the dispatcher.
After quiesce closes the source side, this method waits for every already accepted exchange to complete naturally.
The method returns a Mono that completes when shutdown is fully finished, allowing for reactive shutdown coordination. This ensures no message processing is interrupted mid-flight.
Return
A Mono that completes when all active tasks have finished and shutdown is complete
See also
for deadline-expiry cancellation