Automatically register the metics of PooledByteBufAllocator.DEFAULT

[Bue-von-hon]

Motivation:
Add metrics related to PooledByteBufAllocator that is already exposed by the netty.

Modifications:

• NettyAllocatorMetrics are registered when MoreMeterBinders is initialized.

Result:

• Fixes Add metrics about PooledByteBufAllocator #2633
• Armeria now automatically registers the metics of PooledByteBufAllocator.DEFAULT.

[github-actions]

🔍 Build Scan® (commit: c8ac9d4)

Job name	Status	Build Scan®
build-ubicloud-standard-8-jdk-8	✅	https://ge.armeria.dev/s/lkzadmhdtayry
build-ubicloud-standard-8-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/x2tejzirluozs
build-ubicloud-standard-8-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/yxdire5apwg7w
build-ubicloud-standard-8-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/5jjjtnkdjafiu
build-ubicloud-standard-8-jdk-17-leak	✅	https://ge.armeria.dev/s/kxswtuhlrldbc
build-ubicloud-standard-8-jdk-11	✅	https://ge.armeria.dev/s/qrslt3gnn5euy
build-macos-12-jdk-21	✅	https://ge.armeria.dev/s/dlatuzimpmtn4

[jrhee17]

Micrometer already provides bindings to Netty Metrics (ref: https://docs.micrometer.io/micrometer/reference/reference/netty.html)

I prefer that we either:

1. We close this issue and allow users to add metric bindings themselves. Adding the metric bindings is not difficult and the scope of applying this metric seems ambiguous
2. We add bindings for servers only by default. The name will probably be a combination of local address + ports.

Let me know what you think @line/dx

[ikhoon]

I didn't know that Netty metrics were supported by Micrometer finally.

I prefer automatically setting the metric for the default one (ByteBufAllocator.DEFAULT) when the MoreMeterBinders class is loaded.

[Bue-von-hon]

@ikhoon @jrhee17 @trustin @minwoox
I trust this implementation satisfies your requirements.
If the goal was to consolidate PooledByteBufAllocatorMetrics with eventLoopMetrics or certificateMetrics that would involve substantial modifications. (However, I don't believe that was the intended direction 😅)

[Bue-von-hon]

@ikhoon @jrhee17 @trustin @minwoox gentle ping.

[ikhoon]

I think my intention was not conveyed. Unlike when you first created this PR, Micrometer now supports Netty metrics. Let me add a commit to apply that.

[ikhoon]

Changed the title of this PR to reflect the purpose. 🙇‍♂️

[ikhoon]

Thanks, @Bue-von-hon 👍🙏

[Bue-von-hon]

@jrhee17 @trustin @minwoox gentle ping.

[Bue-von-hon]

@jrhee17 @trustin @minwoox gentle ping.

[jrhee17]

Note: armeria always initializes this class when a client or server is built

[minwoox]

Thanks!

[ikhoon]

@Bue-von-hon Thanks for your effort. That said maintainers are working on various issues and are aware of the status of this PR, so you may not need to keep mentioning us. 🙏