Missing callback-Method "onBind" in org.springframework.boot.context.properties.bind.BindHandler

Hello!

There are several methods for influencing / processing PropertyBinding using org.springframework.boot.context.properties.bind.BindHandler.
But I miss a callback-method like "onBind" that is called when binding takes places.
This method should be called in org.springframework.boot.context.properties.bind.Binder#bindProperty before calling the converter but after resolving placeholders (btw.: I use version 2.6.11).

I try to explain my case as short as possible:
I have to retrieve credentials / URLs etc. from a vault. Unfortunately I cannot use any of the standard-ways to retrieve via configuration / inject the credentials. The only way to do it, is to use a company-specific-proprietary library.
All I want to do is to describe the credentials in my configuration in my own format and to resolve it during binding using the proprietary library, small example:

mysystem:
  secret: secret-spec{'safe':'${safe}','aimUser':'${aimUser}','objectName':'content'}

I build my own BindHandler, that just has a look at the given String and evaluates its specification. Then it uses the proprietary library to retrieve the specified value and returns it.

My solution works fine for Strings (BindHandler#onSuccess, even if it is late!), but fails for URLs etc. because the
Converter cannot resolve something like secret-spec{....}. So I currently use onFailure for this situation.
Not nice, would be perfectly working with a "onBind"-Method.

Please add the mentioned callback to make BindHandler more powerful.

Kind regards
Hans