Why can't I receive the ctx.Done() signal in ctx.stream when closing the client connection when using SSE long connection?

[ppd324]

• With issues:
  • Why can't I receive the ctx.Done() signal in ctx.stream when closing the client connection when using SSE long connection?

Description

When I close the sse long connection, ctx.Done() cannot receive the signal, causing the connection to not be released.

How to reproduce

ctx.Writer.Header().Set("Content-Type", "text/event-stream")
	ctx.Writer.Header().Set("Cache-Control", "no-cache")
	ctx.Writer.Header().Set("Connection", "keep-alive")
	ctx.Writer.Header().Set("Transfer-Encoding", "chunked")
	ctx.Writer.Header().Set("X-Accel-Buffering", "no")
	fmt.Fprintf(ctx.Writer, "data: %s\n\n", "connected")
	ctx.Writer.Flush()
	ctx.Stream(func(w io.Writer) bool {
		select {
		case <-ctx.Request.Context().Done():
			w.Write([]byte("data:[done]\n\n"))
			log.Info("capture result listen done")
			return false
		case cr := <-newChan:
			if cr == nil {
				return false
			}
			data, err := json.Marshal(cr)
			if err != nil {
				log.Errorf("marshal capture result failed, err: %v", err)
				return false
			}
			_, err = fmt.Fprintf(w, "data: %s\n\n", data)
			if err != nil {
				log.Errorf("write capture result failed, err: %v", err)
				return false
			}
			w.(http.Flusher).Flush()
			return true
		}
	})

Expectations

When closing the client connection, print"capture result listen done"

Actual result

After the connection is closed, only failure to send again will trigger the end of the loop.

Environment

• go version: 1.22.0
• gin version (or commit ref): 1.9.1
• operating system: linux