code: protected void unsetVariableRegistry(ServiceReference<VariableRegistry> ref) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
              Tr.debug(tc, "unsetVariableRegistry", ref);
          variableRegistryRef.unsetReference(ref);
      }
docs: Declarative Services method for unsetting the VariableRegistry service reference.
  
  @param ref reference to the service