Header "connection: close" disconnects the client before Response Stream is started

Describe the bug

In our project we use Drogon for HTTP response streaming. However, when client includes connection header that is not keep-alive, response stream is immediaitely closed.

Source code: https://github.com/drogonframework/drogon/blob/cbf63f8fc4d849bbb82eeb1c83fcf8ff953f19f3/lib/src/HttpServer.cc#L981-L990

It is common practice to use connection: close to indicate that connection should be closed after processing is finished*, meaning - after HTTP response stream is done.

In our setup, we needed to patch drogon like this: https://github.com/openvinotoolkit/model_server/pull/3113/commits/8ca2918c04ae9fab77ad157dcd23673971d84420

To Reproduce Steps to reproduce the behavior:

1. Start drogon with streaming response endpoint defined
2. Request with any client including header connection: close
3. Request is immediately rejected

Expected behavior Connection is closed after response streaming is finished.

Desktop (please complete the following information):

• OS: ubuntu, redhat, windows
• Client: any

More context We are using Continue VSCode plugin as a client for code completions: https://github.com/continuedev/continue We use drogon to serve http streaming (code completions), however, this plugin (client) sends connection: close header.