Topic: competing flows of update of the form
There is a form which is representation of any domain model (not to confuse with QAbstractModel). The model can change from time to time, accordingly, the form should react to signals of change of model and be updated. For update to the form it is necessary to fulfill beforehand on the basis of model transient data enough on time calculation. It led to desire to issue calculation by a separate flow. And here there was a problem - if is admitted that model modification can happen continuously then, and starts of calculations on updates can be intersected (procedure of the first update was not up to the end completed yet, and the flow of performance another) begins. A question how to prevent a situation when new update gets into old because of a time delay in executions of flows? That is, if it is abstract how to get rid from: (old) flow 1 was completed and sent to the main flow the message "to launch update with data retrieveds". At this moment it is launched and (new) flow 2 which too sends the message to the main flow "comes to an end to be updated with data retrieveds". What message will be delivered in queue of the main flow are races.