[cleanup][broker] Delete unuse metrics of zk_write_latency and zk_read_latency

[liangyuanpeng]

Motivation

clean up unuse metrics of zk_write_latency and zk_read_latency.

passed CI on self repo CI. https://github.com/pulsar-sigs/pulsar/pull/2

Modifications

Verifying this change

• [x] Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)
• The rest endpoints: (yes / no)
• The admin cli options: (yes / no)
• Anything that affects deployment: (yes / no / don't know)

Documentation

Need to update docs?

• [ ] doc-required

• [x] doc-not-needed

• [ ] doc

• [ ] doc-complete

[liangyuanpeng]

May I ask how can these metrics become unused? Is there any background for this change?

These are legacy code that should be removed after PIP45 Pluggable metadata interface is complete. I think the new metrics is pulsar_storage_write_latency

[tisonkun]

@Shoothzj @merlimat shall we merge this PR now?

[tisonkun]

@liangyuanpeng I think you may merge the latest master to pass CI.

[liangyuanpeng]

@tisonkun Thanks for your update and merged master.

This is just a minor code cleanup that can be merged easily and safely. Please someone review and merge,Thanks.

[liangyuanpeng]

Just random ping someone. Thanks.

@lhotari @hangc0276 @michaeljmarshall

[Shuimo03]

Hi, I have question, Why is the pulsar_storage_write_latency metric an alternative to zk_write_latency?