func (c *greeterServiceProtobufClient) callHello(ctx context.Context, in *HelloRequest) (*HelloResponse, error) {
    out := new(HelloResponse)
    ctx, err := doProtobufRequest(ctx, c.client, c.opts.Hooks, c.urls[0], in, out)
    if err != nil {
        twerr, ok := err.(twirp.Error)