title: iOS Braintree Dropin ui, throws undeclared identifier 'BTAppSwitch`
body: <p>I am using the Braintree drop-in ui for React Native. My issue seems maybe not specific to the library, in which I have already created an issue.</p>
  <p>I'm at the point where I need to add my <code>setReturnURLScheme</code> to my <code>AppDelegate.m</code></p>
  <p>Looks like this</p>
  <pre class="lang-objectivec prettyprint-override"><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
  {
    [BTAppSwitch setReturnURLScheme:@&quot;com.mycompany.myapp.payments&quot;];
    //...
  }
  
  </code></pre>
  <p>However, I receive an error with BTAppSwitch, it says <code>Use of undeclared identifier 'BTAppSwitch'</code>.</p>
  <p>As far as I can tell, I have installed and linked all pods appropriately/automatically, but most instructions are pretty brief. Seems like maybe I'm missing an import statement, but none I've tried have helped. Can someone help please?</p>
  <p>I am using v4</p>