Core Operators and Stream Transformation

Inspect stream emissions, errors, and completions for debugging using the `tap` operator.

Transform stream values using `map` and accumulate state within a stream using `scan`.

Filter streams based on value, position, or time using `filter`, `take`, `debounceTime`, and `throttleTime`.

Control emissions based on value changes or stream activity using `distinctUntilChanged` and `sampleTime`.

Combine multiple streams declaratively using `combineLatest`, `merge`, `concat`, and `zip`.

Execute and collect a group of Observables in parallel using `forkJoin`.

Apply and contrast the four primary flattening operators (`mergeMap`, `switchMap`, `concatMap`, `exhaustMap`) to manage async concurrency patterns.

Handle stream errors gracefully using `catchError` and implement retry logic with `retry`.