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## Type of change
- [ ] Feature
- [x] Bugfix
- [ ] Technical
- [ ] Other :
## Content
`RustMediaLoader` creates the "${cacheDir}/temp/media" dir only once at class creation. Unfortunately when clearing an app's cache this directory will be deleted and the app's process won't be killed, so subsequent usages of the same instance of `RustMediaLoader` will not work because `cacheDirectory` does not exists. This fix makes sure that such directory is always checked and created if needed.
## Motivation and context
Fixes https://github.com/vector-im/element-x-android/issues/1788
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- [ ] Physical
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## Checklist
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- [ ] Changes have been tested on an Android device or Android emulator with API 23
- [ ] UI change has been tested on both light and dark themes
- [ ] Accessibility has been taken into account. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
- [ ] Pull request is based on the develop branch
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Change to `MediaPlayer` API to allow waiting for the player to be in a ready state.
This is needed in order to perform some tasks (e.g. read the media duration, seek) after changing the media file.
Benoit Marty