message: serialise error in response body
diff: @@ -31,9 +31,8 @@ use crate::frame::Serialize;
  impl Serialize for ResponseBody {
  fn serialize(&self, cursor: &mut Cursor<&mut Vec<u8>>) {
  match self {
  - ResponseBody::Error(_error_body) => {
  - todo!();
  - //error_body.serialize(cursor);
  + ResponseBody::Error(error_body) => {
  + error_body.serialize(cursor);
  }
  ResponseBody::Ready | ResponseBody::AuthSuccess => {}
  ResponseBody::Authenticate(auth) => {
  