[improve][docs] Added example to PIP process (apache#21666)

pip/README.md

@@ -85,6 +85,31 @@ The process works in the following way:
 All the future implementation Pull Requests that will be created, should always reference the PIP-XXX in the commit log message and the PR title.
 It is advised to create a master GitHub issue to formulate the execution plan and track its progress.
 
+### Example 
+* Eve ran into some issues with the client metrics - she needed a metric which was missing.
+* She read the code a bit, and has an idea what metrics she wishes to add.
+* She summarized her idea and direction in an email to the DEV mailing list (she located it on
+[Discussions]([url](https://pulsar.apache.org/community/#section-discussions)) section on the website.
+* She didn't get any response from the community, so she joined the next
+[community meeting]([url](https://github.com/apache/pulsar/wiki/Community-Meetings)). There Matteo Merli and Asaf helped 
+setup a channel in Slack to brainstorm the idea and meet on Zoom with a few Pulsar contributors (e.g. Lari and Tison).
+* Once Eve had a good enough context, and good design outline, she opened a new branch in her Pulsar repository, duplicated 
+TEMPLATE.md and created pip-xxx.MD (the number she will take later).
+* She followed the template and submitted the pip as a new PR to pulsar repository.
+* Once the PR was created, she modified the version to match the rules described at step 2, both for PR title and file name.
+* She sent an email to the DEV mailing list, titled "[DISCUSS] PIP-123: Adding metrics for ..." , described shortly in the
+email what the PIP was about and gave a link.
+* She got no response for anyone for 2 weeks, so she nudged the people that helped
+  her brainstorm (e.g. Lary and Tison) and pinged in #dev that she needs more reviewers.
+* Once she got 3 reviews from PMC members and the community had at least a few days from the moment
+  the PR was announceed on DEV, she sent a vote email to the DEV mailing list titled
+  "[VOTE] PIP-123: Adding metrics for ...".
+* She nudged the reviewers to reply with a binding vote, waited for 2-3 days, and then
+  concluded the vote by sending a reply tallying up the binding and non-binding votes. 
+* She updated the PIP with links to discuss and vote emails, and then asked a PMC member
+  who voted +1, to merge (using GitHub mentionon the PR).
+
+
 ## List of PIPs
 
 ### Historical PIPs