A ComponentType may return either with a Success, Failure, or Rework state. The former 2 are probably clear. However, it may happen that a ComponentType requires the set-up of another ComponentType (i.e. of another sub-system) to be done already, although those ComponentType wasn't iterated yet. So a ComponentType may tell the EntityServices that it want to be re-invoked once after the list of ComponentType is iterated first. What exactly happens within the sub-system during entity instantiation depends on the sub-system itself. It may be a cloning of Component as a prototype and linking the clone, or reserving and filling-in a place in a pre-allocated table, or whatever is suitable for the sub-system.
Can you elaborate on this ("Rework")? Maybe some examples of what kinds of problems this is intended to solve? I don't have anything like this in my implementation, so I'm wondering if I'm missing something (or if I solved it another way).