title: Kafka message sent by Debezium does not contain subdocument id in filter field
body: <p>When an <strong>update</strong> operation is executed in MongoDB that has a Debezium connected, a message is sent to Kafka with some properties, including the <strong>filter</strong> field.</p>
  <blockquote>
  <p>filter is a string field that contains the JSON representation of the selection criteria for the update.</p>
  </blockquote>
  <p>The problem is: Debezium only sent the id of the main document and not the subdocuments. For example, if I execute:</p>
  <pre><code>db.myCollection.update({
   &quot;_id&quot;: ObjectId(&quot;mainDocumentId&quot;),
   &quot;mySubdocument._id&quot;: ObjectId(&quot;subdocumentId&quot;)
  },{
   $set: { &quot;mySubdocument.$.myField&quot; : &quot;myValue&quot; }
  })
  </code></pre>
  <p>The message sent to Kafka is:</p>
  <pre><code>{
   ...,
   &quot;filter&quot;: {
    &quot;_id&quot;: { &quot;$oid&quot;: &quot;mainDocumentId&quot; }
   },
   ...
  }
  </code></pre>
  <p>So I can't know exactly which item has been updated.</p>
  <p><strong>There's a way to get all fields used in the filter on update operation?</strong></p>