Go streaming server update yet again

func init() {
    RouteHandler{
        function: func(w http.ResponseWriter, r *http.Request) {
            // Create multipart handler
            mpw := multipart.NewWriter(w)
            hdr := make(textproto.MIMEHeader)
            hdr.Add("Content-Type", "image/png")

            // Write initial response
            w.Header().Set("Content-Type", "multipart/x-mixed-replace; boundary="+mpw.Boundary())
            w.WriteHeader(200)

            // Create a flusher to send frames
            flusher, ok := w.(http.Flusher)
            if !ok {
                return
            }

            // If the request contains a token and the token maps to a valid "brain", start consuming frames from
            // the brain and returning them to the client
            params := r.URL.Query()
            if val, ok := params["token"]; ok && len(val) > 0 {
                if b, ok := SharedMemory["brains"].(map[string]*brain.Brain)[val[0]]; ok && !b.CheckHasExit() {
                    // Keep a checksum of the previous frame to avoid sending frames which haven't changed. Frames cannot
                    // be compared directly (at least efficiently) as they are slices not arrays
                    previousFrameChecksum := [16]byte{}

                    for {
                        if !b.CheckHasExit() {
                            frame, err := b.GetNextFrame(SharedMemory["conf"].(map[string]interface{})["DISPLAY_COL"].(color.Color))
                            if err == nil && md5.Sum(frame) != previousFrameChecksum {
                                // Only write the frame if we succesfully read it and it's different to the previous
                                part, err := mpw.CreatePart(hdr)
                                if err != nil {
                                    log.Println(err)
                                    return
                                }
                                part.Write(frame)
                                //mpw.Close()

                                // Update the checksum to this frame
                                previousFrameChecksum = md5.Sum(frame)

                                // Flush the buffer to make sure the frame is sent ASAP
                                flusher.Flush()
                            }
                            // Limit the framerate to reduce CPU usage
                            <-time.After(time.Duration(SharedMemory["conf"].(map[string]interface{})["FPS_LIMITER_INTERVAL"].(int)) * time.Millisecond)
                        } else {
                            // The brain has exit so there is no more we can do - we are braindead :P
                            return
                        }
                    }
                }
            }
        },
    }.Register("/stream", "/stream.png")
}