code: private void performChecks(Contextual<?> contextual) {
          if (tc.isEntryEnabled())
              Tr.entry(tc, "performChecks", this);
  
          if (!isActive()) {
              throw new ContextNotActiveException();
          }
  
          if (contextual == null) {
              throw new IllegalArgumentException("Contextual parameter should not be null");
          }
  
          if (tc.isEntryEnabled())
              Tr.exit(tc, "performChecks");
      }
docs: basic error checks we perform before each get/destroy call