Added post-header-set-test function
Added post-header-set-test function

kemadz/gorequest,fromkeith/gorequest,QuentinPerez/gorequest,roth1002/gorequest,vicanso/gorequest,parnurzeal/gorequest,julianshen/gorequest,rockneurotiko/gorequest,jqs7/gorequest,going/requests,csrgxtu/gorequest