startProcessInstanceWithForm cannot intialize businesskey

Flowable Engine
1

When I use startProcessInstanceWithForm ,I can not specify the businesskey for it .And I see the source code,
ProcessInstanceBuilder processInstanceBuilder = createProcessInstanceBuilder()
.processDefinitionId(processDefinitionId)
.outcome(outcome)
.startFormVariables(variables)
.name(processInstanceName);
why don’t you include “.businessKey” in it?Is it no need to use businessKey in form process?
Looking forward to your answer{^ . ^}

2

When not just use the ProcessInstanceBuilder directly, instead of the runtimeService.startProcessInstanceWithForm (...) method?
Then you can add whichever additional parameters you need. Something like this should work:

ProcessInstanceBuilder processInstanceBuilder = runtimeService.createProcessInstanceBuilder()
    .processDefinitionId(processDefinitionId)
    .outcome(outcome)
    .startFormVariables(variables)
    .name(processInstanceName)
    .businessKey(myBusinessKey)
    .start();