This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
const dehydrated = prevState.dehydrated;
        if (dehydrated !== null) {
          if (!didSuspend) {
            return updateDehydratedSuspenseComponent(
              current,
              workInProgress,
              dehydrated,
              prevState,
              renderLanes,
            );
          } else if (
            (workInProgress.memoizedState: null | SuspenseState) !== null
          ) {
            
            
            workInProgress.child = current.child;
            
            
            workInProgress.flags |= DidCapture;
            return null;
          } else {
            
            
            const nextPrimaryChildren = nextProps.children;
            const nextFallbackChildren = nextProps.fallback;
            const fallbackChildFragment = mountSuspenseFallbackAfterRetryWithoutHydrating(
              current,
              workInProgress,
              nextPrimaryChildren,
              nextFallbackChildren,