title: check if tuple is null or not
body: <p>how do I check whether a variable of a tuple datatype is null or not in C#?</p>
  <pre><code>                 var allUsers = new List&lt;PersonEntity&gt;();
                   var response = await context.CallActivityAsync&lt;(List&lt;PersonEntity&gt; entities, TableContinuationToken continuationToken)&gt;(
                                                                  nameof(ChildEntitiesFilterFunction),
                                                                  new ChildEntitiesFilterRequest
                                                                  {
                                                                      ContinuationToken = null,
                                                                      Query = filter,
                                                                      SyncJob = request.SyncJob,
                                                                      SourceTableName = directReportCloudTableName,
                                                                  });
                  allUsers.AddRange(response.entities);
  </code></pre>
  <p>adding an if condition if (response == null) didn't work</p>
  <p><a href="https://i.stack.imgur.com/qdMzK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qdMzK.png" alt="enter image description here" /></a></p>
  <p>adding if conditions if (response.entities == null) if (response.ContinuationToken) are giving nullreference exception error.</p>