Add support for Custom Order not based on SObject/Record dependencies

[alesremta-ext43767]

Is your feature request related to a problem? Please describe.
Sometimes you need to explicitly split record updates into "custom" buckets or impose an order of Operations that is not strictly based on Record dependencies.
e.g.
Automating permission management including Profile (licence) swap. We have to ensure this order:

• Delete Permission Set (Group) Assignments
• Delete Permission Set Licence Assignments (SF does not always do this automatically)
• Update User Profile
• Insert Permission Set Licence (not All PS will grant licence automatically)
• Insert Permission Set (Group) Assignments
  Different order can fail, though we still want this to be one atomic operation.

Describe the solution you'd like
a) re-introduce Custom Order - would support above scenario as long as we do not need custom buckets within SObject (unlikely)
b) add "Generic Work" option, similar to ApexCommon's fflib__SObjectUnitOfWork.registoerWork(IDoWork) which will allow "chaining" two instances of DML
e.g.

static DML dmlWork = new DML();
static DML secondPassWork = new DML();
...
register stuff
...
dmlWork.toSave(secondPassWork);
dmlWork.commitWork();

[pgajek2]

Thanks @alesremta-ext43767 , as always, great points!

Solution a) might be difficult to implement. The order we had used SObjectType to define the execution order, but didn’t support operation type order (insert, update, etc.). Supporting that would require significant configuration changes, which could make the logic harder to understand.

That’s why I’m leaning toward option b), which seems much simpler to implement and, in my opinion, makes the code easier to read.

Workaround for now:
Option A)
Make sense only when you have a simple case.

Just commit secondPassWork before the dmlWork.

secondPassWork.commitWork();
dmlWork.commitWork();

Option B) (Probably this is what you are looking for, let me know)
We do have DML.Hook (it's not documented yet - I need to add that, sorry!). It should work just fine for now.

public class MyContainer {
    static DML dmlWork = new DML();
    static DML secondPassWork = new DML();

    public void execute() {
        //...
        // register stuff
        //...
        dmlWork.commitHook(new UserManagementHook());
        dmlWork.commitWork();
    }

    public class UserManagementHook implements DML.Hook {
       public override before() {
          MyContainer.secondPassWork.commitWork();
       }
    
       public void after(DML.Result result) {
         // ...
       }
    }
}