splunk proxy

Hi, We are planning to migrate to migrate to splunk SaaS. The architecture is to use intermediate forwarder and proxy. data flow will be splunk universal forwarder ----> Intermediate forwarder---> Proxy ----> Splunk SaaS. Our security constraints requires the data to go through proxy. Is it something which can be done or we need to have direct connection to splunk SaaS from Intermediate forwarder ? what kind of proxy does it support. Our proxy settings would to put credentials. Regards