Bug: Streaming endpoints aren't flushing hte http writers.

[perbu]

Hi.

I'm working on a streaming (text/event-stream) example and I noticed the generated code doesn't flush the output properly. I've tracked this down to the code in pkg/codegen/templates/strict/strict-interface.tmpl, which looks something like this:

                    if closer, ok := response.Body.(io.ReadCloser); ok {
                        defer closer.Close()
                    }
                    _, err := io.Copy(w, response.Body)
                    return err

io.Copy will buffer the response, which would be fine for most cases, but would add an arbitrary delay on text/event-stream, which is pretty bad as the delay can easy be 10+ seconds. text/event-streams are often time-sensitive.

What we wanna do in here is to check the content-type and if it is text/event-stream, we wanna flush after each write. similar code is in the httputil/reverseproxy part of the stdlib in case anyone wants to see other places where text/event-stream is a special case.

Since fixing this would touch the generated code I thought I'd at least bring the topic up before trying to fix this myself. Let me know how I should proceed.