func loadComments(root intTree) commentTree {
    result := commentTree{}
    var wg sync.WaitGroup
    loadCommentsInner(&result, root, &wg)
    wg.Wait()
    return result
}

func loadCommentsInner(resNode *commentTree, node intTree, wg *sync.WaitGroup) {
    wg.Add(len(node.children))
    for _, res := range node.children {
        child := &commentTree{}
        resNode.children = append(resNode.children, child)
        res := res
        go func() {
            defer wg.Done()
            loadCommentsInner(child, res, wg)
        }()
    }
    resNode.value = getCommentById(node.id)
}