== Background
We would like to know the usage of the sidebar once its built and how introducing a sidebar affects the overall clickthrough rates of the sidebar links
== Acceptance criteria
[] Build sidebar instrumentation according to the guidelines set in https://docs.google.com/spreadsheets/d/1gf0gHuo8pXUZDL8aQDrf7QdWBn-dM2tCG4tGZIEBuoU/edit#gid=0
[] Feature flag instrumentation as we would only want to run it on the test wikis in the beginning
[] Instrumentation should be run on both the new version and old version of the skin on a given wiki
[] Initial sampling rate: 20%. Sampling rate should be configurable so we can change it later if necessary.
[] Event tracking code is scoped to WikimediaEvents as much as possible
== Developer notes
Consider the Minerva click tracking code and if it makes sense to generalize some of its functions given the similarities between these 2 schemas.
= QA steps
[] TODO: Get Jon to turn on sampling on the BC https://gerrit.wikimedia.org/r/#/c/operations/mediawiki-config/+/607136 Enable click tracking in Vector on beta cluster
[] Visit https://en.wikipedia.beta.wmflabs.org/wiki/Main_Page and verify an init event is fired when the page unloads (you'll need to click 'preserve network requests')
[] Click a link in the sidebar and verify a click event is fired when the page unloads (you'll need to click 'preserve network requests')
[] Click the toggle menu button and verify a click event is fired when the page unloads (you'll need to click 'preserve network requests')
[] Verify an init event is fired in legacy Vector when the page unloads (you'll need to click 'preserve network requests')
[] Verify a click event is fired in legacy Vector when the page unloads (you'll need to click 'preserve network requests')
== QA Results - Beta
| **AC** | **Status** | **Details** |
| ----- | ----- | ----- |
| 1 | ✅ | T250282#6268200 |
| 2 | ✅ | T250282#6268200 |
| 3 | ✅ | T250282#6268200 |
| 4 | ✅ | T250282#6268200 |
| 5 | ✅ | T250282#6268200 |