     open var headers = [String: String]()
     open var requestAdapter: RequestAdapter?
     open var requestRetrier: RequestRetrier?
+    open var mandatoryQueryParams = Params()
 
     /**
      Create a webservice instance.

        let c = defaultCall()
        c.httpVerb = verb
        c.URL = url
        c.params = params
        return c
    }
    

        return r.fetch().resolveOnMainThread()
    }
    
    open func addMandatoryQueryParameter(key: String, value: Any) -> WS {
        mandatoryQueryParams[key] = value
        return self
    }
    
    open func addMandatoryQueryParameter(params: Params) -> WS{
        mandatoryQueryParams.merge(params) { (current, _) in current }
        return self
    }
    
}

public extension Promise {
