protected void onReturning(Request request, Processor processor, Response response) {
        if (Trace.Level.Step.includes(trace.getTraceLevel()) || trace.getForceTimestamps()) {
            int traceAt = trace.getForceTimestamps() ? 1 : trace.getTraceLevel();
            trace.trace("Return " + processor, traceAt);
        }
    }
A hook called when a processor returns, either normally or by throwing.
Overriding methods must call super.onReturning

@param request   the processing request
@param processor the processor which returned
@param response  the response returned, or null if the processor returned by throwing
container-core/src/main/java/com/yahoo/processing/execution/Execution.java