Events not raised on iPhone

Hi,
it seems that the event "loadstop" on the iPhone is never raised.
The documentation says that "_self" is not supported on iOS, so the pages are opened into the external browser Safari.
Is this the reason why the events don't work?
Are the events usable on iOS?

If I run this code into a Ionic4 app:

`const browserRef = this.iab
.create(
paymentUrl,
'_self',
'toolbar=yes,fullscreen=no,hidden=no,location=no,clearsessioncache=yes,clearcache=yes,zoom=no'
);

// Event raised when the browser loads a page
browserRef.on('loadstop').subscribe(event => {
console.log('event:', event);
alert('url:' + event.url);
}`

The alert is never printed on iOS, on Android it works.

I'm using:

`iPhone 7

iOS 12.3.1`

The app is done with Ionic4:
`Ionic:
Ionic CLI : 5.2.1
Ionic Framework : @ionic/angular 4.3.0
@angular-devkit/build-angular : 0.13.9
@angular-devkit/schematics : 7.2.4
@angular/cli : 7.3.8
@ionic/angular-toolkit : 1.5.1
Cordova:
Cordova CLI : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : android 8.0.0, ios 5.0.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 4.1.0, (and 12 other plugins)
Utility:
cordova-res : 0.6.0
native-run : 0.2.2


C:\ProveElectron\bitsharingapp>ionic cordova plugins
> cordova.cmd plugin ls
cordova-plugin-device 2.0.2 "Device"
cordova-plugin-file 6.0.1 "File"
cordova-plugin-inappbrowser 3.0.0 "InAppBrowser"
cordova-plugin-insomnia 4.3.0 "Insomnia (prevent screen sleep)"
cordova-plugin-ionic-keyboard 2.1.3 "cordova-plugin-ionic-keyboard"
cordova-plugin-ionic-webview 4.1.0 "cordova-plugin-ionic-webview"
...
es6-promise-plugin 4.2.2 "Promise"`

No source file or test is named. Start by reproducing the Ionic 4/Cordova InAppBrowser create('_self', ...) call and comparing the loadstop subscription on iOS and Android; done means determining whether loadstop is supported on iOS and fixing the event or documenting the limitation.

Written by the indexing model from the issue text.