public IObservable<Unit> ExecuteAsync(ExecutionContext context)
{
context.AssertNotNull(nameof(context));
context.CancellationToken.ThrowIfCancellationRequested();
return context
.WaitWhilePausedAsync()
.SelectMany(_ => this.speechService.SpeakAsync(this.speechText, context.CancellationToken))
.FirstAsync()
.RunAsync(CancellationToken.None);
}