Calculating API Lag

I'm working on developing a drop rate tracker, however I'm bumping into an issue with lag from the api.When I retrieve data from api.guildwars2.com/v2/characters/Character_Name/inventory, the data is out of date... historically by anywhere between 30-50s (estimate).So far I've been getting around this by setting a 60s countdown timer, however recently this lag has been getting worse, and is now almost always over a minute out of sync.I realise this is simply the nature of managing a server such as this, and want you to know I'm not complaining about it... but when you have to wait 5 minutes for the cache to clear, actually testing to make sure this timer is right in-program is basically impossible.

Is there any way to find out the current lag for endpoint requests in the api?Would it be possible to include a timestamp on requests? That way It'd be possible to automate the countdown timer to sync with the server on first request.

All character endpoints are cached in the API for 5 minutes. In addition, the instance server of the map you are playing on only writes your inventory to the backend servers the API is reading in batches and not real time.

I realise that, but is there a way to work out when the next batch will be sent to the api and sync accordingly?Without knowing the batch delay/ calculation times, there's no way to guarantee that the data you receive is the data you want when you're working with a time sensitive dataset which can be affected by in game drops/inventory management.

No, there is no way.