The latter runs on every PR and is a prerequisite for merging.

If you run the sanity check locally with the `./gradlew sanityCheck`, you can see the binary compatibility error in the output.
It looks like the following:

```
Execution failed for task ':architecture-test:checkBinaryCompatibility'.
> A failure occurred while executing me.champeau.gradle.japicmp.JApiCmpWorkAction
   > Detected binary changes.

If you've found a bug, please contribute a failing test case so we can study and fix it.

If you have a new feature idea, please build it in an external library. There are
[many libraries][works_with_okhttp] that sit on top or hook in via existing APIs. If you build
something that integrates with OkHttp, tell us so that we can link it!

Before code can be accepted all contributors must complete our
[Individual Contributor License Agreement (CLA)][cla].

- Favour a working external library if appropriate.  There are many examples of OkHttp libraries that can sit on top or hook in via existing APIs.
- Get working code on a personal branch with tests before you submit a PR.
- OkHttp is a small and light dependency.  Don't introduce new dependencies or major new functionality.

    rare occasion we may reject it.

**3. Review**

-   For a valid PR, reviewer (person familiar with the code/functionality)
    checks if the PR looks good or needs additional changes.
-   If all looks good, the reviewer will approve the PR.
-   If a change is needed, the contributor is requested to make the suggested
    change.
-   You make the change and submit it for the review again.