message: mempack: add is_end
diff: @@ -80,6 +80,11 @@ impl<'a> ReadBuf<'a> {
  }
  }
  + /// Check if we reach the end of the buffer
  + pub fn is_end(&self) -> bool {
  + self.left() == 0
  + }
  +
  /// Skip a number of bytes from the buffer.
  pub fn skip_bytes(&mut self, sz: usize) -> Result<(), ReadError> {
  self.assure_size(sz)?;
  