Recently Google’s John Mueller commented on twitter that Google never supports crawl delay in robot.txt file. But this does not mean that user can’t slow down the crawling process of Google. On the other hand, Bing’s Frédéric Dubut replies in tweet by saying Bingbot supports crawl delay.
Tweet By John Mueller
We never supported crawl-delay in robots.txt — the numbers given there tend to be unrealistic for the most part.
— ? John ? (@JohnMu) December 12, 2019
Tweet By Frédéric Dubut
Yes Bingbot supports crawl-delay.
— Frédéric Dubut (@CoperniX) December 12, 2019
The crawl settings are still present in the Google Search Console. The user can set the rate of Google’s crawling rate under search console.