Mohammad Nejati

This looks like a Asio issue. Could you please open an issue here: https://github.com/chriskohlhoff/asio/issues? What compiler flags are you using? It would help if you could come up with a...

I think the reason might be that `request_header` and `response_header` are two separate classes, and `keep_alive` is common to both request and response messages. Moving it to the header would...

> the implementation of `keep_alive()` depends on knowing if the message is a request or a response, which is not possible in `basic_fields`. I think `keep_alive` is a common field...

Have you considered using an [experimental::basic_concurrent_channel](https://www.boost.org/doc/libs/develop/doc/html/boost_asio/reference/experimental__basic_concurrent_channel.html) to send new subscribe requests to the other thread?