In implementing the 'Performance' feature of Firebase, I got the following error attempting to sync the Gradle:
Plugin with id 'com.google.firebase.firebase-perf' not found.
I implemented it following instructions here: https://firebase.google.com/docs/perf-mon/get-started-android. In particular it directs you to specify the classpath dependency to com.google.firebase:perf-plugin in your root-level (project-level) Gradle file, not he app-level:
Here are my Gradles, app-level left, project-level right: