runtime/runtime.go
func RunInBackground(c context.Context, f func(c context.Context)) error {
	req := &pb.StartBackgroundRequestRequest{}
	res := &pb.StartBackgroundRequestResponse{}
	if err := internal.Call(c, "system", "StartBackgroundRequest", req, res); err != nil {
		return err
	}
	sendc <- send{res.GetRequestId(), f}
	return nil
}
func RunInBackground(c context.Context, f func(c context.Context)) error {
	req := &pb.StartBackgroundRequestRequest{}
	res := &pb.StartBackgroundRequestResponse{}
	if err := internal.Call(c, "system", "StartBackgroundRequest", req, res); err != nil {
		return err
	}
	sendc <- send{res.GetRequestId(), f}
	return nil
}
// RunInBackground runs f in a background goroutine in this process.
// f is provided a context that may outlast the context provided to RunInBackground.
// This is only valid to invoke from a service set to basic or manual scaling.