Use metric-schema to report JVM Buffer Pool metrics

[mpritham]

Before this PR

We weren't using metric-schema when registering the JVM Buffer Pool metrics. Using metric-schema gives us some nice tooling, like markdown file generation allowing devs to find all published metrics easily.

After this PR

==COMMIT_MSG==
Use metric-schema to report JVM Buffer Pool metrics
==COMMIT_MSG==

Possible downsides?

N/A

[changelog-app]

Generate changelog in changelog/@unreleased

What do the change types mean?

• feature: A new feature of the service.
• improvement: An incremental improvement in the functionality or operation of the service.
• fix: Remedies the incorrect behaviour of a component of the service in a backwards-compatible way.
• break: Has the potential to break consumers of this service's API, inclusive of both Palantir services
  and external consumers of the service's API (e.g. customer-written software or integrations).
• deprecation: Advertises the intention to remove service functionality without any change to the
  operation of the service itself.
• manualTask: Requires the possibility of manual intervention (running a script, eyeballing configuration,
  performing database surgery, ...) at the time of upgrade for it to succeed.
• migration: A fully automatic upgrade migration task with no engineer input required.

Note: only one type should be chosen.

How are new versions calculated?

• ❗The break and manual task changelog types will result in a major release!
• 🐛 The fix changelog type will result in a minor release in most cases, and a patch release version for patch branches. This behaviour is configurable in autorelease.
• ✨ All others will result in a minor version release.

Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

Use metric-schema to report JVM Buffer Pool metrics

Check the box to generate changelog(s)

• Generate changelog entry

[carterkozak]

If you want to be particularly defensive against nulls, you could do something like this:

Suggested change

	if (poolName.equals("direct")) {
	if ("direct".equals(poolName)) {

Or Objects.equals(poolName, "direct") which handles both values being null (although that's impossible for a constant string). I wouldn't expect getName to ever return null either, but we've seen crazier things...

Entirely up to you whether to change this :-]

[mpritham]

Ah good call. I'll change this to the first idea: "direct".equals(poolName) for the null protection.

[carterkozak]

Thanks!

[autorelease3]

Released 0.93.0