code: func (c *ComputeUtil) startInstance() error {
  	op, err := c.service.Instances.Start(c.project, c.zone, c.instanceName).Do()
  	if err != nil {
  		return err
  	}
  
  	log.Infof("Waiting for instance to start.")
  	return c.waitForRegionalOp(op.Name)
  }
docs: // startInstance starts the instance.