new (?uri:String)
contentType:String
data:Bytes
enableResponseHeaders:Bool
followRedirects:Bool
formData:Map<String, Dynamic>
headers:Array<HTTPRequestHeader>
method:HTTPRequestMethod
responseData:T
responseHeaders:Array<HTTPRequestHeader>
responseStatus:Int
timeout:Int
uri:String
userAgent:String
withCredentials:Bool
cancel ():Void
load (?uri:String):Future<T>