# Functions
NewControl creates a new controller-agnostic instance.
Register registers a new controller.
# Constants
Default mode is Relaxed.
Disabled controller are stopped, hooks are not run.
Optional controllers are Disabled if they can't start, otherwise they are Required.
Relaxed controllers are Disabled if they can't start, hook failures are not errors.
Required controllers must start, hooks must succeed.
# Interfaces
Control is the interface for triggering controller-/domain-specific post-decision actions.
Controller is the interface all resource controllers must implement.