title: how to measure the payload size for Azure Table Entity Group Transaction?
body: <p>According to MSDN (http://msdn.microsoft.com/en-us/library/windowsazure/dd894038.aspx), </p>
  
  <ul>
  <li>The transaction can include at most 100 entities, and its total payload may be no more than 4 MB in size.</li>
  </ul>
  
  <p>Question) Before sending a group-transaction request, how can we measure the payload size in order to guarantee that the size does not exceed 4MB?</p>
  
  <p>thanks in advance!</p>