It gets rid of holding state of the io.Reader offset (which is anyways held by
the vfs.FileDescriptor struct. It is also odd using a io.Reader becuase we
using io.ReaderAt to interact with the device. So making a io.ReaderAt wrapper
makes more sense.
Most importantly, it gets rid of the complexity of extracting the file reader
from a regular file implementation and then using it. Now we can just use the
regular file implementation as a reader which is more intuitive.
PiperOrigin-RevId: 260846927
Ayush Ranjan