var (
    user   User
    songs  []Songs
    photos []Photos
)
err := async.Run(ctx,
    func(ctx context.Context) error {
        user, err = user.Get(ctx, id)
        return err
    },
    func(ctx context.Context) error {
        songs, err = song.GetByUserID(ctx, id)
        return err
    },
    func(ctx context.Context) error {
        photos, err = photo.GetByUserID(ctx, id)
        return err
    },
)
if err != nil {
    log.Error(err)
}

runner := async.NewRunner(tasks...).WithLimit(3)
if err := runner.Run(ctx); err != nil { 
    log.Error(e)
}