Can I add data for additional field using datastore crawl after file crawl?

(from github.com/JiroSato)
Hi!
Can I add data for additional field using datastore crawl after file crawl?
I would like to integrate the results of data store crawl and data store crawl.

(from github.com/marevol)
No. DataStore Crawling cannot merge with File System Crawling, but you can invoke CrawlerClient to access other documents in DataStore Crawling.

(from github.com/JiroSato)
Thank you for your reply.

I’d appreciate it if you give me more information about DataStore Crawling.
I referred to this page, but I couldn’t find enough information to understand how to invoke CrawlerClient.

I’d like to use text extraction of FileCrawl with DataStore Crawling.