using System;
using System.Text.RegularExpressions;
public class Test
{
    public static void Main()
    {   
        string msg= "__cfduid=d2eec71493b48565be764ad44a52a7b191399561601015; expires=Mon, 23-Dec-2019 23:50:00 GMT; path=/; domain=.planetminecraft.com; HttpOnly";
        var charSetOccurences = new Regex(@"\s*([^=;]+)(?:=([^=;]+))?");
        var charSetMatches = charSetOccurences.Matches(msg);
        foreach (Match match in charSetMatches)
        {
            Console.WriteLine(match.Groups[1].Value + "\n" + match.Groups[2].Value + "\n");
        }
    }
}

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