Unpredictable start of rendering #21600
Description
When a Bevy (0.17.2) application is launched, it does not start rendering correctly right away. The first few frames are always completely transparent (zeroed alpha channel) and on subsequent frames, it seems to be very hard to predict, if Bevy has actually started writing data to the GPU buffers. This is a problem when using Bevy as a rendering tool for animations, because ideally, you'd want to start the animation immediately upon application launch.
In previous versions of Bevy (<=0.16), this problem already existed for certain features, but in most cases, it could be alleviated by disabling the asynchronous compilation of the rendering pipeline within the RenderPlugin struct. But since the release of 0.17, this does not seem to work anymore, as the initial frame now consistently displays as transparent regardless of the synchronous_pipeline_compilation setting (tested on MacOS and Linux).
This bug can be reproduced by running the examples in https://github.com/paulkre/bevy_image_export/tree/v0.15.0 and looking at the exported images within the ./out directory.