public static CrawlerConfiguration PdfTextExtractProcessor(this CrawlerConfiguration crawlerConfiguration,
			int? maxDegreeOfParallelism = null)
		{
			PdfBoxTextExtractorProcessorPipelineStep filterTextExtractorProcessor =
				new PdfBoxTextExtractorProcessorPipelineStep(maxDegreeOfParallelism.GetValueOrDefault(Environment.ProcessorCount));
			crawlerConfiguration.AddPipelineStep(filterTextExtractorProcessor);
			return crawlerConfiguration;
		}
        public static CrawlerConfiguration PdfTextExtractProcessor(this CrawlerConfiguration crawlerConfiguration,
                                                                   int?maxDegreeOfParallelism = null)
        {
            PdfBoxTextExtractorProcessorPipelineStep filterTextExtractorProcessor =
                new PdfBoxTextExtractorProcessorPipelineStep(maxDegreeOfParallelism.GetValueOrDefault(Environment.ProcessorCount));

            crawlerConfiguration.AddPipelineStep(filterTextExtractorProcessor);
            return(crawlerConfiguration);
        }