Seeking after play on video doesn't always work.

## 🐛 Bug Report

I save out the current playback position and try to seek after we play. We tried to loop into the change of state and that works sometimes.

### Expected behavior
It will seek to the new position.

### Reproduction steps
https://github.com/jamesmontemagno/Hanselman.Forms/pull/133

### Configuration

**Version:** 1.x

**Platform:**
- [ ] :iphone: iOS
- [x] :robot: Android
- [ ] :checkered_flag: WPF
- [ ] :earth_americas: UWP
- [ ] :apple: MacOS
- [ ] :tv: tvOS
- [ ] :monkey: Xamarin.Forms

I have only tried it on Android thus far.

Start with the reproduction described in PR 133 and trace the Android video playback state around saving the current position and seeking after playback begins. Verify the behavior on Android by reproducing the intermittent failure, then confirm that seeking consistently reaches the new position.

Written by the indexing model from the issue text.