negative read/write value on error

[ozanh]

Hi,
Thank you for smb2 👍
I encountered a panic while copying a bufio.Reader to smb2.File which is due to a write error with a negative write size.
io.Writer, io.Reader, io.ReaderAt should return non-negative value even on error (https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/bufio/bufio.go;drc=99f1bf54eb502e123e60c605212a616146fbe86a;l=559)

If it is possible, I would like to open a PR to replace all returning -1 with 0 values from io.Writer, io.Reader, io.ReaderAt , etc. implementations. Please let me know If I am missing something.