title: Node Lambda timing out firebase-admin SDK
body: <p>I'm trying to send push notifications through Firebase Cloud Messaging from a node js lambda in AWS.</p>
  <p>My function works and I receive the notification on my phone, however the lambda keeps timing out (even at 20s timeout). I can see in logs my lambda callback is being called. It appears that something is preventing the lambda from returning.</p>
  <p>I initialise with:</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>const serviceAccount = require('./firebaseKey.json');
  
  admin.initializeApp({
      credential: admin.credential.cert(serviceAccount),
      databaseURL: 'xxx',
  });</code></pre>
  </div>
  </div>
  </p>
  <p>and send with:</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>const fcmResponse = await admin.messaging().sendToDevice(fcmToken, message);</code></pre>
  </div>
  </div>
  </p>
  <p>My hunch is that it's something here preventing it from returning as everything else is pretty vanilla.</p>
  <p>Does anyone have any ideas as to what's causing the timeouts?</p>