Function handle_http_request 

async fn handle_http_request<R, S>(
    request: Request<Incoming>,
    context: &ProxyContext<R>,
    listener_isolation: (usize, IpAddr),
) -> Result<Response<String>, Error>
where
    R: Runtime,
    S: AsyncRead + AsyncWrite + Send + Sync + Unpin + 'static,

Handle a single HTTP request.

This function is invoked by hyper.