title: Get all available values in Office.context.mailbox.item for Outlook
body: <p>Is there an api to access get all available values async in <code>Office.js</code>, specifically <code>Office.context.mailbox.item</code> in Outlook? </p>
  
  <p>I do not see anything in the <a href="https://docs.microsoft.com/en-us/office/dev/add-ins/reference/objectmodel/requirement-set-1.7/office.context.mailbox.item" rel="nofollow noreferrer">docs</a>. </p>
  
  <p>I need to capture 10 or so fields, and to date have only implemented with callbacks, e.g. </p>
  
  <pre><code>var ITEM = Office.context.mailbox.item;
  var wrapper =  //fn to parse results and call next field getAsync as cb
  ITEM.end.getAsync(wrapper);
  </code></pre>