receiveMessage
Creates a flux of messages for the specified subscription.
This method should return a reactive stream of messages that are destined for the given aggregate. The implementation should handle message sourcing, filtering, and any necessary transformations.
Return
A Flux of messages for the subscription. May be empty if no messages are available.
Parameters
subscription
The subscription to receive messages for. Must not be null.
Throws
if the subscription is invalid or unsupported.
if there are issues with message sourcing or connectivity.