Quota Policy Start Time: Is it possible to have a dynamic value for the quota start time?

[#1]

Suppose I want to start counting requests when the developer is created, not when they send the first request.

I was thinking that it would be great to have a dynamic start time ?

<StartTime ref="verifyapikey.verify-api-key.developer.created_at" />

This requirement is associated to the fact that subscription plans in payment platforms are usually billed on the day of the subscription was created (and developer created as well).