hunk.code_window:     return subject;
     }
     private materializeInnerObservable(observable: Observable<any>, outerFrame: number): TestMessage[] {
       const messages: TestMessage[] = [];
       observable.subscribe(
         (value) => {
           messages.push({ frame: this.frame - outerFrame, notification: nextNotification(value) });
         },
  
hunk.labels: keep keep keep keep keep replace replace keep keep
hunk.after_edit:     observable.subscribe({
         next: (value) => {
  
hunk.file_path: src/internal/testing/TestScheduler.ts
hunk.type: replace
file: import { mergeMap } from './mergeMap';
  import { ObservableInput, OperatorFunction, ObservedValueOf } from '../types';
  import { isFunction } from '../util/isFunction';
  
  /* tslint:disable:max-line-length */
  export function concatMap<T, O extends ObservableInput<any>>(
    project: (value: T, index: number) => O
  ): OperatorFunction<T, ObservedValueOf<O>>;
  /** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
  export function concatMap<T, O extends ObservableInput<any>>(
    project: (value: T, index: number) => O,
    resultSelector: undefined
  ): OperatorFunction<T, ObservedValueOf<O>>;
  /** @deprecated The `resultSelector` parameter will be removed in v8. Use an inner `map` instead. Details: https://rxjs.dev/deprecations/resultSelector */
  export function concatMap<T, R, O extends ObservableInput<any>>(
    project: (value: T, index: number) => O,
    resultSelector: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
  ): OperatorFunction<T, R>;
  /* tslint:enable:max-line-length */
  
  /**
   * Projects each source value to an Observable which is merged in the output
   * Observable, in a serialized fashion waiting for each one to complete before
   * merging the next.
   *
   * <span class="informal">Maps each value to an Observable, then flattens all of
   * these inner Observables using {@link concatAll}.</span>
   *
   * ![](concatMap.png)
   *
   * Returns an Observable that emits items based on applying a function that you
   * supply to each item emitted by the source Observable, where that function
   * returns an (so-called "inner") Observable. Each new inner Observable is
   * concatenated with the previous inner Observable.
   *
   * __Warning:__ if source values arrive endlessly and faster than their
   * corresponding inner Observables can complete, it will result in memory issues
   * as inner Observables amass in an unbounded buffer waiting for their turn to
   * be subscribed to.
   *
   * Note: `concatMap` is equivalent to `mergeMap` with concurrency parameter set
   * to `1`.
   *
   * ## Example
   *
   * For each click event, tick every second from 0 to 3, with no concurrency
   *
   * ```ts
   * import { fromEvent, concatMap, interval, take } from 'rxjs';
   *
   * const clicks = fromEvent(document, 'click');
   * const result = clicks.pipe(
   *   concatMap(ev => interval(1000).pipe(take(4)))
   * );
   * result.subscribe(x => console.log(x));
   *
   * // Results in the following:
   * // (results are not concurrent)
   * // For every click on the "document" it will emit values 0 to 3 spaced
   * // on a 1000ms interval
   * // one click = 1000ms-> 0 -1000ms-> 1 -1000ms-> 2 -1000ms-> 3
   * ```
   *
   * @see {@link concat}
   * @see {@link concatAll}
   * @see {@link concatMapTo}
   * @see {@link exhaustMap}
   * @see {@link mergeMap}
   * @see {@link switchMap}
   *
   * @param {function(value: T, ?index: number): ObservableInput} project A function
   * that, when applied to an item emitted by the source Observable, returns an
   * Observable.
   * @return A function that returns an Observable that emits the result of
   * applying the projection function (and the optional deprecated
   * `resultSelector`) to each item emitted by the source Observable and taking
   * values from each projected inner Observable sequentially.
   */
  export function concatMap<T, R, O extends ObservableInput<any>>(
    project: (value: T, index: number) => O,
    resultSelector?: (outerValue: T, innerValue: ObservedValueOf<O>, outerIndex: number, innerIndex: number) => R
  ): OperatorFunction<T, ObservedValueOf<O> | R> {
    return isFunction(resultSelector) ? mergeMap(project, resultSelector, 1) : mergeMap(project, 1);
  }
  