[SR-Users] Re: Handling branch-level append_hf()

Hi, I’ve got a situation where I catch a 302 redirect in a failure_route (branch #1), and use the Contact to set a custom header (append_hf()). This custom header is utilised on the subsequent branch (branch #2), but if that branch fails (e.g. due to 4xx-5xx response), the custom header is not preserved on subsequent branches (branch #3+). What’s the best way to preserve it across subsequent branches? The documentation for msg_apply_changes() says it cannot be used once the transaction is already created, and in any case, I have other branch-level changes in branch #2 that I _would_ like to revert on subsequent branch attempts (i.e. branch #3). I can certainly devise a transaction-persistent vehicle for this value which can be checked on every branch, but I wondered if there’s an easier and more best-practical way.