Ensure that event slot and condition slot allocation use a common interface during Gaudi integration
Gaudi's event slot allocation mechanism currently uses a polling-based interface, where event slot allocation failure is reported through an error code that requests the Gaudi scheduler to try again later. The proposed condition slot allocation mechanism uses a more elaborate asynchronous allocation mechanism based on futures, which allows it to be used more efficiently by the Gaudi scheduler, at the cost of interface inconsistency.
During Gaudi integration, some effort should be expended into removing this interface inconsistency, either by moving the event slot allocation mechanism to futures, or by falling back to polling on condition slot allocation.