[PR #1489] Updated RequestRetrier completion to be escaping.
[PR #1489] Updated RequestRetrier completion to be escaping.

Allows the `RequestRetrier` to perform async work before executing the
`completion` closure.
antigp/Alamofire,Farteen/Alamofire,dgdosen/Alamofire,Lomotif/Alamofire,Noobish1/Alamofire,iosheadhunter/Alamofire,tonyli508/AlamofireDomain,Vkt0r/Alamofire,richardPFisk/Alamofire,Lomotif/Alamofire,dgdosen/Alamofire,tonyli508/AlamofireDomain,Noobish1/Alamofire,Alamofire/Alamofire,yimajo/Alamofire,Alamofire/Alamofire,easyui/Alamofire,twobitlabs/Alamofire,mbhuta/Alamofire,Vkt0r/Alamofire,jschmid/Alamofire,twobitlabs/Alamofire,antigp/Alamofire,easyui/Alamofire,jschmid/Alamofire,mbhuta/Alamofire,richardPFisk/Alamofire,yimajo/Alamofire,iosheadhunter/Alamofire,Farteen/Alamofire