This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
(current.memoizedState: null | SuspenseState) !== null
    ) {
      
      
      
      
      
      if (
        nextProps.fallback !== undefined &&
        nextProps.unstable_avoidThisFallback !== true
      ) {
        suspenseContext = addSubtreeSuspenseContext(
          suspenseContext,
          InvisibleParentSuspenseContext,
        );
      }
    }
  }
  suspenseContext = setDefaultShallowSuspenseContext(suspenseContext);
  pushSuspenseContext(workInProgress, suspenseContext);