This central operation sits at a crossroad and is used
- from external clients to fed new work to the Scheduler
- from Workers to engage into execution of the next Activity
- recursively from the execution of an Activity-chain
From these requirements the semantics of behaviour can be derived
regarding the GroomingToken and the result values, which indicate
when follow-up work should be processed
Ensure the GroomingToken mechanism indeed creates an
exclusive section protected against concurrent corruption:
Use a without / with-protection test and verify
the results are exact vs. grossly broken
T thread holding the »Grooming Token" is permitted to
manipulate scheduler internals and thus also to define new
activities; this logic is implemented as an Atomic lock,
based on the current thread's ID.
Notably both Layers are conceived as functionality providers;
only at Scheduler top-Level will functionality be combined with
external dependencies to create the actual service.
