title: How to get stacktrace from Flutter?
body: <p>I have a Android/iOS app developed using <code>Flutter</code> through Visual Studio Code. When I run it on Android >=5.0 or any version of iOS it works flawlessly, however <strong>it crashes immediately</strong> when I run it on Android 4.x (<em>Unfortunately, app has stopped</em>). </p>
  
  <p>I want to fix it, but <code>Flutter</code>doesn't show me what is happening.</p>
  
  <p>I tried to run through VSCode pushing F5 button and also using command line <code>flutter run</code>, but neither shows me something that I could work with. I tried to run with <code>trace</code> command <code>[Flutter trace run]</code>, but it says <code>The --debug-port argument must be specified</code> and I don't know what it means.</p>
  
  <p>I just need a stacktrace or a line error showing me what is the problem. Do I have to configure something on VSCode?</p>