title: Create events with a specific Id
body: <p>I need to create events that are &quot;updated&quot; by an external application.
  Every time an entity is updated on the application (e.g: the description) I have to mirror that to the corresponding event in the Outlook calendar.</p>
  <p>The idea is to avoid storing the calendar event ids in a database.
  To do that the initial solution was to give to those events the same id as the entities that are on the application.
  Unfortunately this seems to be not possible on microsoft-graph-api as the Id is read-only.
  The other options are:</p>
  <ul>
  <li>Open extensions
  <ul>
  <li>Seems that they are not queryable. I can't filter for a value of the extension, correct?</li>
  </ul>
  </li>
  <li>Extended properties
  <ul>
  <li>Works and provides a way to filter using single value extended properties (<a href="https://docs.microsoft.com/en-us/graph/api/singlevaluelegacyextendedproperty-post-singlevalueextendedproperties?view=graph-rest-1.0" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/graph/api/singlevaluelegacyextendedproperty-post-singlevalueextendedproperties?view=graph-rest-1.0</a>). My only concerns are that I can't understand if this is a legacy/deprecated/going to be deprecated approach or if it's valid</li>
  </ul>
  </li>
  <li>Schema extensions
  <ul>
  <li>Haven't checked that option. Pros/cons?</li>
  </ul>
  </li>
  </ul>
  <p>Is there any other way to solve that requirement?
  Any hint to share?</p>
  <p>Many thanks in advance</p>