在.NET中计算目录大小的最佳方法是什么？

using System;
using System.IO;

public static class DirectoryHelper
{
    public static long GetDirectorySize(string directoryPath)
    {
        if (!Directory.Exists(directoryPath))
        {
            throw new ArgumentException($"Directory '{directoryPath}' does not exist.");
        }

        long size = 0;

        foreach (string filePath in Directory.GetFiles(directoryPath))
        {
            FileInfo fileInfo = new FileInfo(filePath);
            size += fileInfo.Length;
        }

        foreach (string subDirectoryPath in Directory.GetDirectories(directoryPath))
        {
            size += GetDirectorySize(subDirectoryPath);
        }

        return size;
    }
}