Interesting project. However, I wonder if the developer has considered accessibility for blind users. Both Android and iOS have built-in accessibility, but whenever an application takes text rendering into its own hands, accessibility for that text becomes the responsibility of the application. I don't know what actual performance requirements led to the development of Bypass, but to me, the extra work required to regain accessibility would probably not be worth the performance boost in this case.
Accessibility is maintained, Bypass doesn't do any of the text rendering, it simply figures out the styles and text and then passes that on to the text containers on each platform.
Bypass may be accessible to blind users on Android; I'm not currently set up to verify this easily. But it's not on iOS.
The reason is that on iOS, Bypass implements its own UIKit views. It does use the CoreText framework to render the text into a CoreGraphics context, but that doesn't help accessibility. The views would need to implement the UIAccessibility protocol.
The iOS implementation has the capability to use different rendering methods. I know that there is one that can render to a label that should work with accessibility.
[1]: https://github.com/dreamwieber/AttributedMarkdown.git