The supported start events are as follows (see the preceding image, left to right):
None
Message:
<bpmn2:messageEventDefinition>
Timer:
<bpmn2:timerEventDefinition>
Escalation:
<bpmn2:escalationEventDefinition>
Conditional:
<bpmn2:conditionalEventDefinition>
Error:
<bpmn2:errorEventDefinition>
Compensation:
<bpmn2:compensationEventDefinition>
Signal:
<bpmn2:signalEventDefinition>