title: Unity3D how to enable --stacktrace
body: <p>I'm getting this error when building gradle.</p>
  
  <blockquote>
    <ul>
    <li><p>What went wrong: Execution failed for task ':transformClassesWithJarMergingForRelease'.</p>
    
    <blockquote>
      <p>com.android.build.api.transform.TransformException: java.util.zip.ZipException: duplicate entry:
      com/google/android/gms/common/util/VisibleForTesting.class</p>
    </blockquote></li>
    <li><p>Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.</p></li>
    </ul>
  </blockquote>
  
  <p>I will solve this problem if I can see which modules are conflicting. Any help appreciated!</p>