add
Add an interceptor to observe and potentially veto saga step execution.
Interceptors are invoked before and after each step (Before → After, LIFO for After), and after each compensation action. An interceptor returning InterceptorOutcome.Veto from a StepPhase.Before phase prevents the step from executing.
Default implementation throws UnsupportedOperationException — only overridden in SagaExecutorImpl.
Parameters
interceptor
The interceptor to add