将C＃代码哈希复制到PHP

I have to replicate C# hash from the code below into PHP. I have been searching but didn't find a solution so far.

private string createHash(string stringToHash)
    {
        // Byte[] originalBytes;

        MD5 hash = MD5.Create();

        hash = new MD5CryptoServiceProvider();

        // originalBytes = ASCIIEncoding.Default.GetBytes(stringToHash);

        byte[] data = hash.ComputeHash(Encoding.Default.GetBytes(stringToHash));

        StringBuilder sBuilder = new StringBuilder();

        for (int i = 0; i < data.Length; i++)
        {

            sBuilder.Append(data[i].ToString("x2"));

        }

        return sBuilder.ToString();
    }

Thanx for you help!

PHP has an in-built function - MD5

<?php
    $hash = md5("plain text");
    echo $hash;
?>