title: Prevent multiple findOne calls triggered by real time stream
body: <p>I have a stream of events that roughly looks like this:</p>
  <pre><code>{ hash: 'XXXX', foo: 'bar }
  </code></pre>
  <p>On each hit, I gotta look up that hash in a db using mongoose</p>
  <pre><code>await Model.find({hash: XXX})
  </code></pre>
  <p>Sometimes, I get hit with a bunch of events that share the same hash and currently it triggers a bunch of <code>.find()</code> calls that essentially return the same thing.</p>
  <p>How can I optimize this process and prevent <code>.find()</code> from being called multiple times if the hash is the same.</p>