/// <inheritdoc /> public Task <IExistsResponse> SourceExistsAsync(ISourceExistsRequest request, CancellationToken cancellationToken = default(CancellationToken) ) => Dispatcher.DispatchAsync <ISourceExistsRequest, SourceExistsRequestParameters, ExistsResponse, IExistsResponse>( request, cancellationToken, (p, d, c) => LowLevelDispatch.ExistsSourceDispatchAsync <ExistsResponse>(p, c) );