code: public synchronized void addDeferredReferenceData(DeferredReferenceData refData) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              Tr.entry(tc, "addDeferredReferenceData", "this=" + this, refData);
          }
  
          if (deferredReferenceDatas == null) {
              deferredReferenceDatas = new LinkedHashMap<DeferredReferenceData, Boolean>();
              if (parent != null && deferredReferenceDataEnabled) {
                  parent.addDeferredReferenceData(this);
              }
          }
          deferredReferenceDatas.put(refData, null);
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              Tr.exit(tc, "addDeferredReferenceData");
          }
      }
docs: Add a child deferred reference data to this scope.