optimize: support http1 automatic keepalive setting

[funky-eyes]

What is the purpose of the change?

由于ab压测工具默认是短连接，当使用该工具压测时，针对短连接请求，没有将对应的channel设置该ChannelFutureListener.CLOSE listener时，将使ab压测工具进程hang住，故增加自动识别请求是否需要保持长连接来解决该问题。

Since the ab benchmarking tool uses short connections by default, when using this tool for benchmarking, if the corresponding channel is not set with the ChannelFutureListener.CLOSE listener for short connection requests, it will cause the ab benchmarking tool process to hang. Therefore, adding automatic recognition of whether the request needs to keep the connection alive can solve this problem.

Checklist

• Make sure there is a GitHub_issue field for the change.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 12.50000% with 7 lines in your changes missing coverage. Please review.

Project coverage is 60.76%. Comparing base (a9e4910) to head (a6dfb8e).

Files with missing lines	Patch %	Lines
...bbo/remoting/http12/netty4/h1/NettyHttp1Codec.java	0.00%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                3.3   #15019      +/-   ##
============================================
- Coverage     60.76%   60.76%   -0.01%     
- Complexity    10866    10868       +2     
============================================
  Files          1882     1882              
  Lines         85983    85990       +7     
  Branches      12876    12878       +2     
============================================
+ Hits          52246    52250       +4     
- Misses        28289    28295       +6     
+ Partials       5448     5445       -3     

Flag	Coverage Δ
integration-tests	33.00% <12.50%> (-0.13%)	⬇️
samples-tests	29.22% <12.50%> (-0.01%)	⬇️
unit-tests	58.92% <12.50%> (+0.01%)	⬆️

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[oxsean]

private boolean keepAlive;

[funky-eyes]

private boolean keepAlive;

done

[oxsean]

Not flipping the boolean will make the code better understood:

            if (keepAlive) {
                ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT, promise);
            } else {
                ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT, promise).addListener(ChannelFutureListener.CLOSE);
            }

[funky-eyes]

Not flipping the boolean will make the code better understood:

            if (keepAlive) {
                ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT, promise);
            } else {
                ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT, promise).addListener(ChannelFutureListener.CLOSE);
            }

done

[oxsean]

Could you please test whether SSE is work fine?
https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events

[funky-eyes]

Could you please test whether SSE is work fine? https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events

In Spring, i can use SseEmitter to send messages, but how should this be done in Dubbo? Are there any related examples?