Delay the Emission of Values from an RxJS Observable

This lessons teaches about delay and delayWhen: simple operators that time shift each emission from the source Observable by a specified amount of time.

🚨 Since we are importing interval from RxJS, we don't need to preface our Observables with Rx.Observable. You can no longer .{operator}, you need to .pipe({operator}) instead. To link together multiple Observables and Operators, the method is a bit different. You call zip first, then list your Observables, your functions, then pipe your Operators.