Upload multiple files to azure blob storage in parallel

ParallelUploadToBlobStorage.cs

class Program
{
    static void Main(string[] args)
    {
        var stopwatch = new Stopwatch();
        stopwatch.Start();
        UploadToBlobAsync().Wait();
        stopwatch.Stop();
        Debug.WriteLine("Elapsed time in seconds: " + stopwatch.ElapsedMilliseconds / 1000);
    }

    private static async Task UploadToBlobAsync()
    {
        var storageAccount = CloudStorageAccount.Parse(@"UseDevelopmentStorage=true");
        var blobClient = storageAccount.CreateCloudBlobClient();
        var container = blobClient.GetContainerReference("container" + Guid.NewGuid().ToString("N").ToLowerInvariant());
        await container.CreateIfNotExistsAsync().ConfigureAwait(false);

        var baseDir = @"E:\Source\Ghost\core";
        var files = Directory.GetFiles(baseDir, "*", SearchOption.AllDirectories);

        using (var semaphoreSlim = new SemaphoreSlim(2))
        {
            var tasks = files.Select(async file =>
            {
                await semaphoreSlim.WaitAsync().ConfigureAwait(false);
                try
                {
                    var blobName = ConvertToRelativeUri(file, baseDir);
                    var blob = container.GetBlockBlobReference(blobName);

                    using (var fileStream = File.OpenRead(file))
                    {
                        await blob.UploadFromStreamAsync(fileStream).ConfigureAwait(false);
                    }
                }
                finally
                {
                    semaphoreSlim.Release();
                }
            });

            await Task.WhenAll(tasks).ConfigureAwait(false);
        }
    }

    private static string ConvertToRelativeUri(string filePath, string baseDir)
    {
        var uri = new Uri(filePath);
        if (!baseDir.EndsWith(Path.DirectorySeparatorChar.ToString()))
        {
            baseDir += Path.DirectorySeparatorChar.ToString();
        }
        var baseUri = new Uri(baseDir);
        return baseUri.MakeRelativeUri(uri).ToString();
    }
}