message: (fix): is_next_nil now "peeking" instead of reading
diff: @@ -621,10 +621,12 @@ impl Read for ReadDecoder {
  }
  fn is_next_nil(&mut self) -> Result<bool, DecodeError> {
  + let position = self.view.buffer.position();
  let format = Format::get_format(self)?;
  if format == Format::Nil {
  Ok(true)
  } else {
  + self.view.buffer.set_position(position);
  Ok(false)
  }
  }
  