用C#格式化电话号码的最快方法？

using System;
using System.Text.RegularExpressions;

public class Program
{
    public static void Main(string[] args)
    {
        string phoneNumber = "13800138000";
        string formattedPhoneNumber = FormatPhoneNumber(phoneNumber);
        Console.WriteLine(formattedPhoneNumber);
    }

    public static string FormatPhoneNumber(string phoneNumber)
    {
        string formattedPhoneNumber = Regex.Replace(phoneNumber, "[^0-9]", "");
        return formattedPhoneNumber;
    }
}