on
Called after every macroReplicationStatistics.collect(result) across all execution paths (runSimulation, runInitialSample, runMacroReplications).
The default implementation records the current half-width to the convergence history saver when saveConvergenceHistory is true and at least two observations have been collected (the minimum needed for a valid half-width).
Subclasses may override this to add their own post-replication instrumentation; they should call super.onMacroReplicationCompleted() to preserve history recording.