How to get processInstanceDescriptoin using kie api.

Issue

• How to get processInstanceDescription from the ProcessInstance object which is acquired from the kie session.

public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {

        RuntimeEngine runtimeEngine = runtimeManager.getRuntimeEngine(ProcessInstanceIdContext.get(workItem.getProcessInstanceId()));       
        KieSession kieSession = runtimeEngine.getKieSession();
        ProcessInstance processInstance = kieSession.getProcessInstance(workItem.getProcessInstanceId());
       String processId = processInstance.getProcessId();       
           //Wanted to fetch process-instance-description
    }