We are using CA API Gateway software form factor v9.4 running on RHEL7.
We have a requirement where within a service/proxy, we need to invoke "route via https assertion" to one of backend end-point and forget about a response from that end-point and complete the further execution so ideally, we just need to invoke the back-end API which is there for internal purpose and it should not add any slowness due to it to actual intended request.
I have checked and this is something not possible within route assertion.
Release : 9.4
Component : API GTW ENTERPRISE MANAGER
At the moment, Asynchronous HTTP call is not supported.