title: ElasticSearch NEST API update value to null
body: <p>I am using NEST api and I am having trouble using <code>client.Update&lt;T, K&gt;</code> method to update a value to <code>null</code></p>
  
  <p>Is there any parameter or settings when calling update that will allow for <code>null</code> to be set trough nest api?</p>
  
  <p>I know I can do it with sense.</p>