Azure blob storage coping from another storage account blob

AzureBlobCopyBatch.cs

using System;
using System.IO;
using Microsoft.WindowsAzure;
using Microsoft.WindowsAzure.StorageClient;

namespace AzureBlobBatch
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                if (args == null || args.Length < 4)
                {
                    Console.WriteLine("Required arguments is [source storage account name] [source storage key] " +
                        "[destination storage account name] [destination storage key] [container name (optional)]");
                    Console.ReadKey();
                    return;
                }

                string containerName = null;
                if (args.Length == 5)
                {
                    containerName = args[4];
                }

                var sourceCredentials = new StorageCredentialsAccountAndKey(args[0], args[1]);
                var sourceAccount = new CloudStorageAccount(sourceCredentials, true);
                var sourceClient = sourceAccount.CreateCloudBlobClient();

                var destinationCredentials = new StorageCredentialsAccountAndKey(args[2], args[3]);
                var destinationAccount = new CloudStorageAccount(destinationCredentials, true);
                var destinationClient = destinationAccount.CreateCloudBlobClient();

                if (containerName != null)
                {
                    var container = sourceClient.GetContainerReference(containerName);
                    Copy(container, destinationClient, container.Name);
                }
                else
                {
                    foreach (var container in sourceClient.ListContainers())
                    {
                        Copy(container, destinationClient, container.Name);
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.ReadKey();
            }
        }

        private static void Copy(CloudBlobContainer sourceContainer, CloudBlobClient destinationClient, string containerName)
        {
            var destinationContainer = destinationClient.GetContainerReference(containerName);

            destinationContainer.CreateIfNotExist();

            foreach (var blob in sourceContainer.ListBlobs(new BlobRequestOptions
            {
                AccessCondition = AccessCondition.None,
                BlobListingDetails = BlobListingDetails.All,
                UseFlatBlobListing = true
            }))
            {
                var relativeUri = sourceContainer.Uri.MakeRelativeUri(blob.Uri);
                var uri = new Uri(destinationContainer.Uri, relativeUri).ToString();
                var destinationBlob = destinationContainer.GetBlockBlobReference(uri);
                if (destinationBlob.Exists())
                {
                    continue;
                }

                var sourceBlob = sourceContainer.GetBlockBlobReference(blob.Uri.ToString());
                using (var stream = new MemoryStream())
                {
                    sourceBlob.DownloadToStream(stream);
                    stream.Seek(0, SeekOrigin.Begin);

                    destinationBlob.UploadFromStream(stream);

                }

                Console.WriteLine("copied " + relativeUri);
            }
        }
    }

    public static class BlobExtensions
    {
        public static bool Exists(this CloudBlob blob)
        {
            try
            {
                blob.FetchAttributes();
                return true;
            }
            catch (StorageClientException e)
            {
                if (e.ErrorCode == StorageErrorCode.ResourceNotFound)
                {
                    return false;
                }
                throw;
            }
        }
    }
}