[improve][pip] PIP-322: Pulsar Rate Limiting Refactoring

[lhotari]

Motivation

This contains PIP-322: Pulsar Rate Limiting Refactoring. Check the pip-322.md document for details.

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

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[asafm]

I think this change is good to Pulsar functionality, and more important - to Pulsar developers and even users trying to figure out the code.

I read the background reading blog linked (from the section you mentioned), and the text in the PIP. I can honestly say I understand only 30% of how the solution would really look like, so without prior background it's hard for me personally to give proper feedback. I usually stay clear of reading PRs implementing PIP as they harder to read and take more time than PIPs :) so I try to make sure I can understand what I can from the PIP.

I truly appreciate how this overall addition to Pulsar raises the bar for Pulsar 💪

[tisonkun]

Approved as PIP voted passed - https://lists.apache.org/thread/2s9hkmxovz1gop2031wk4v8skm270zh6

Thanks for driving this effort @lhotari!