code: public void setLauncher(File launcherBinary) throws IOException {
      OperaLauncherRunner.assertLauncherGood(launcherBinary);
      options.get(LAUNCHER).setValue(launcherBinary);
    }
docs: Specifies launcher to use.  If {@link #autostart()} is false, it will not be used.
  
  @param launcherBinary the launcher binary
  @throws IOException if there is a problem with the provided launcher