code: public void error(OutputStream os,
                      String to,
                      HeadersAmp headers,
                      ErrorAmp error)
      throws IOException
    {
      init(os);
  
      OutH3 out = _out;
  
      if (out == null)
        return;
  
      if (log.isLoggable(Level.FINEST)) {
        log.finest("error" + error
                   + " (in " + this + ")" + " {to:" + to + ", " + headers + "}");
      }
  
      out.writeLong(MessageTypeHamp.ERROR.ordinal());
      writeHeaders(out, headers);
      
      writeFromAddress(out, to);
  
      out.writeString(error.getCode().toString());
      out.writeString(error.getMessage());
      out.writeObject(error.getDetail());
  
      //out.flushBuffer();
      out.flush();
    }
docs: Sends a message to a given address