title: Does Mongoose always use only one connection instance per request created in nodejs?
body: <p>Why does Mongoose always use only one connection instance per request created in nodejs?</p>
  
  <pre><code>const mongo_uri = `mongodb+srv://${process.env.MONGO_USER}:${process.env.MONGO_PWD}@${process.env.MONGO_URL}/${process.env.MONGO_DB}?retryWrites=true&amp;w=majority`;
  mongoose.connect(mongo_uri, {
      useNewUrlParser: true,
      useUnifiedTopology: true
  });
  const serverStatus = () =&gt; {
      return [{
          mongoose: {
              state: 'up',
              dbState: mongoose.STATES[mongoose.connection.readyState]
          }
      }]
  };
  //  Plug into middleware.
  app.use('/healthcheck', require('express-healthcheck')({
      healthy: serverStatus
  }));
  </code></pre>