var csa = CloudStorageAccount.Parse(BLOB_CONNECTION_STRING);
var client = csa.CreateCloudBlobClient();
var containerRefernece = client.GetContainerReference(CONTAINER_NAME);
var blobrefernce = containerRefernece.GetAppendBlobReference(BLOB_NAME);
var ms = new MemoryStream();
var sr = new StreamWriter(ms);
sr.WriteLine(message);
ms.Seek(0, SeekOrigin.Begin);
await blobrefernce.AppendBlockAsync(ms);
windowsAzure.Storage StorageException: The value for one of the HTTP headers is not in the correct format.