@academyoffetishes: you can setup DomainRule for this generic http and limit it to 1 concurrent download
Settings->Advanced Settings->GeneralSettings.domainrules
Code:
[ {
"domainPattern" : "bunkr.is",
"enabled" : true,
"maxSimultanDownloads" : 1,
"allowToExceedTheGlobalLimit" : false
} ]