Xamarin.Essentials: File System Helpers

Hello,
I try to use File System Helpers for my project. But for Android the stream returned by FileSystem.OpenAppPackageFileAsync doesn't support random access. CanSeek is false, Length and Position are not supported. This complicates things a lot. The only way to get a file size for example is to read per byte and count them. This itself may not be a big issue but reading is extremely slow too. Many times slower than for UWP. For UWP it works fully. I mean random access is supported and reading is fast as it's supposed to be.
Why is this? It kind of defeats the purpose of File System Helpers since it's nearly unusable for Android.