calc md5 sum for a files in a blob storage (azure data lake gen2)

blobMd5.cs

using Azure.Storage;
using Azure.Storage.Files.DataLake;
using Azure.Storage.Files.DataLake.Models;
using System;
using System.Collections.Generic;
using System.IO;
using System.Security.Cryptography;
using System.Threading.Tasks;

namespace CopyToBlob
{
    class Program
    {
        public static IEnumerable<string> GetDirFiles(string path) {
            foreach (string file in Directory.GetFiles(path, "*", SearchOption.AllDirectories))
            {
                yield return file;
            }
        }
        public static DataLakeServiceClient GetDataLakeServiceClient(string accountName, string accountKey)
        {
            StorageSharedKeyCredential sharedKeyCredential =
                new StorageSharedKeyCredential(accountName, accountKey);

            string dfsUri = "https://" + accountName + ".dfs.core.windows.net";

            return new DataLakeServiceClient
                (new Uri(dfsUri), sharedKeyCredential);
        }
        public static async Task UploadFileBulk(FileStream fileStream, string dirName, string fileName, DataLakeFileSystemClient fileSystemClient)
        {
            DataLakeDirectoryClient directoryClient =
                fileSystemClient.GetDirectoryClient(dirName);
            var p = new Progress(fileStream.Length);
            var opts = new DataLakeFileUploadOptions { 
                 ProgressHandler = p,
                TransferOptions = new StorageTransferOptions { 
                    MaximumTransferSize = 100003838
                }
            };
            DataLakeFileClient fileClient = directoryClient.GetFileClient(fileName);
            await fileClient.UploadAsync(fileStream, opts);
        }

        static async Task Main(string[] args)
        {
            var ds = GetDataLakeServiceClient("", "");
            var fs = ds.GetFileSystemClient("");

            var dir = fs.GetDirectoryClient("/cs/ScoringData");
            var appender = File.AppendText("ScoringData-datalake.chk");
            foreach (var path in dir.GetPaths())
            {
                var file = fs.GetFileClient(path.Name);
                using (var stream = file.OpenRead())
                {
                    var provider = new MD5CryptoServiceProvider();
                    var md5 = provider.ComputeHash(stream);
                    string sum = BitConverter.ToString(md5).Replace("-","").ToLower();
                    appender.WriteLine($"{path.Name}\t{sum}");
                    appender.Flush();
                    Console.WriteLine($"{path.Name}\t{sum}");
                }
            }
            appender.Close();
        }
    }
}