C# compare different Encoding pattern between UTF8 and UTF32 based on Md5

using System;
using System.Text;
using System.IO;
using System.Security.Cryptography;

 static void Main(string[] args)
        {
            CompareFileGetBytes("lyf.txt");
            Console.ReadLine();
        }

 static void CompareFileGetBytes(string fileFullName)
        {
            byte[] fileReadAllBytes = File.ReadAllBytes(fileFullName);
            string fileReadAllBytesMd5 = GetBytesMd5(fileReadAllBytes);

            string utf8Md5 = string.Empty;
            using (StreamReader reader = new StreamReader(fileFullName))
            {
                string textResult = reader.ReadToEnd();
                byte[] utf8Bytes = Encoding.UTF8.GetBytes(textResult);
                utf8Md5 = GetBytesMd5(utf8Bytes);
            }

            string utf32Md5 = string.Empty;
            using (StreamReader utf32Reader = new StreamReader(fileFullName))
            {
                string textResult = utf32Reader.ReadToEnd();
                byte[] utf32Bytes = Encoding.UTF32.GetBytes(textResult);
                utf32Md5 = GetBytesMd5(utf32Bytes);
            }


            Console.WriteLine($"fileReadAllBytesMd5:{fileReadAllBytesMd5},utf8Md5:{utf8Md5}");

            if (string.Equals(fileReadAllBytesMd5, utf8Md5))
            {
                Console.WriteLine($"{nameof(fileReadAllBytesMd5)} is equal with {nameof(utf8Md5)}!");
            }
            else
            {
                Console.WriteLine($"{nameof(fileReadAllBytesMd5)} is not equal with {nameof(utf8Md5)}!");
            }

            Console.WriteLine($"utf8Md5:{utf8Md5},utf32Md5:{utf32Md5}");
            if (string.Equals(utf8Md5, utf32Md5))
            {
                Console.WriteLine($"{nameof(utf8Md5)} is equals with {nameof(utf32Md5)}");
            }
            else
            {
                Console.WriteLine($"{nameof(utf8Md5)} is not  equals with {nameof(utf32Md5)}");
            }
        }

        static string GetBytesMd5(byte[] bytesData)
        {
            StringBuilder md5Builder = new StringBuilder();
            using(MD5CryptoServiceProvider md5=new MD5CryptoServiceProvider())
            {
                byte[] md5Bytes = md5.ComputeHash(bytesData);
                for(int i=0;i<md5Bytes.Length;i++)
                {
                    md5Builder.Append(md5Bytes[i].ToString("x2"));
                }
            }
            return md5Builder.ToString();
        }

I had validated that different encoding mode can generate different result,they are not identical.

Besides,the File.ReadAllBytes may based on UTF8 because they render the identical result!