Mutli instance does not work when using a ReceiveTaskActivityBehavior based prototype scoped spring bean

The trigger (signal) method of ServiceTaskDelegateExpressionActivityBehavior does not setup the multi instance behavior correctly when using a delegateExpression to a prototype scoped spring bean. This causes the "loop" to terminate when triggerd/signalled.

The AbstractBpmnActivityBehavior.multiInstanceActivityBehavior reference is not assigned before the activity is triggered/signalled.

The setup;
- A service task with multi instance properties setup.
- A delegateExpression to a prototype scoped spring bean.
- The bean is a subsclass of ReceiveTaskActivityBehavior and thus requires a trigger/signal to continue.

Inizia tracciando ServiceTaskDelegateExpressionActivityBehavior.trigger/signal e AbstractBpmnActivityBehavior.multiInstanceActivityBehavior, quindi confronta come viene inizializzato un delegateExpression con scope prototype per una sottoclasse di ReceiveTaskActivityBehavior. Riproduci la configurazione con una service task multi-istanza e un delegate di receive task segnalato; il lavoro è completato quando il ciclo multi-istanza continua invece di terminare.

Scritto dal modello di indicizzazione a partire dal testo della issue.