hunk.code_window: import { of, concat, timer, Observable } from 'rxjs';
   /** @test {throttle} */
   describe('throttle operator', () =>  {
     it('should immediately emit the first value in each time window', () =>  {
       const e1 =   hot('-a-xy-----b--x--cxxx-|');
       const e1subs =   '^                    !';
       const e2 =  cold( '----x                ');
       const e2subs =  [' ^   !                ',
  
hunk.labels: keep keep keep replace keep keep keep keep keep
hunk.after_edit: describe('throttle', () =>  {
  
hunk.file_path: spec/operators/throttle-spec.ts
hunk.type: replace
file: <div class="form-select-menu">
    <button class="form-select-button" (click)="toggleOptions()">
      <strong>{{label}}</strong><span *ngIf="showSymbol" class="symbol {{selected?.value}}"></span>{{selected?.title}}
    </button>
    <ul class="form-select-dropdown" *ngIf="showOptions">
      <li *ngFor="let option of options; index as i"
          [class.selected]="option === selected"
          role="button"
          tabindex="0"
          (click)="select(option, i)"
          (keydown.enter)="select(option, i)"
          (keydown.space)="select(option, i); $event.preventDefault()">
        <span *ngIf="showSymbol" class="symbol {{option.value}}"></span>{{option.title}}
      </li>
    </ul>
  </div>
  