add delay validation test
add delay validation test

fjordan/gocrawl,mantyr/gocrawl,morephp/gocrawl,vizewang/gocrawl,abhishekgahlot/gocrawl,fjordan/gocrawl,morephp/gocrawl,vizewang/gocrawl,PuerkitoBio/gocrawl,abhishekgahlot/gocrawl,mantyr/gocrawl