When trying to replace the headers, set them empty or to remove the default methods and add new ones, the method remove_header has no impact on (at least) a request message type.

For example client::request<<remove_header("Content-Type") and client::request<<remove_header("Accept") used for removing default headers has no effect in removing the mentioned headers. Adding a header aftwerwards will add it additionally, hence the desired action, replacing the default headers with custom ones might not happen.