code: public String startWorkflow(StartWorkflowRequest startWorkflowRequest) {
          Preconditions.checkNotNull(startWorkflowRequest, "StartWorkflowRequest cannot be null");
          return stub.startWorkflow(
                  protoMapper.toProto(startWorkflowRequest)
          ).getWorkflowId();
      }
docs: Starts a workflow
  
  @param startWorkflowRequest the {@link StartWorkflowRequest} object to start the workflow
  @return the id of the workflow instance that can be used for tracking