title: ionic 2 - inappbrowser "browser.on(...).subscribe is not a function" error
body: <p>I follow this <a href="http://ionicframework.com/docs/native/in-app-browser/" rel="noreferrer">http://ionicframework.com/docs/native/in-app-browser/</a> document for use inappbrowser and try with below steps :</p>
  
  <p>1- install </p>
  
  <pre><code>ionic cordova plugin add cordova-plugin-inappbrowser 
  
   npm install --save @ionic-native/in-app-browser
  </code></pre>
  
  <p>2 - Add this plugin to app.module.ts  provider</p>
  
  <p>3 - add to constructor : </p>
  
  <pre><code>constructor(private iab: InAppBrowser) { }
  </code></pre>
  
  <p>4- and use it in launch method like this :</p>
  
  <pre><code>import { InAppBrowser,InAppBrowserEvent} from '@ionic-native/in-app-browser';
  
  launch(urlc){
        let url = 'https://example.com/';
        let browser = this.iab.create(url, '_blank', 'location=yes');
        browser.on('loadstart').subscribe((ev: InAppBrowserEvent) =&gt; {
            this.close_status=true;
        });
    }
  </code></pre>
  
  <p>but when serve and call launch method I see this error :</p>
  
  <pre><code>Runtime Error
  browser.on(...).subscribe is not a function
  </code></pre>