Connection:close ignored?

I just got bitten by an annoying incompatibility between Hypercorn 0.17.3 and Icinga check_http.

check_http sends "HTTP/1.0" and "connection: close" and expects the server to, well, close the connection.
Hypercorn ignores that, it sends content-length: and expects the client to stop reading after X bytes.

Is there a way to teach hypercorn not to do that?