title: Function returns an instance of Future<String> instead of String
body: <p>I have a streambuilder, within, I want to calculate the distance for each different card of the streambuilder. It calculates the distance if I print it in the terminal, but on the screen it shows: Instance of future &lt; String >. Is there a fix for this? I tried making a variable and run set state, but the value has to be different for each card of the streambuilder.</p>
  
  <pre><code>Future&lt;String&gt; distanceInMeters({double uLat, double uLong}) async {
    if (uLat == null &amp;&amp; uLong == null) {
      return "";
    } else {
      double distanceInMeters =
          await Geolocator().distanceBetween(uLat, uLong, 52.3546274, 4.8285838);
      String distance = distanceInMeters.toString();
      return "$distance";
    }
  }
  </code></pre>