This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
}
      }
    }
    const child = mountChildFibers(
      workInProgress,
      null,
      nextChildren,
      renderLanes,
    );
    workInProgress.child = child;
    let node = child;
    while (node) {
      
      
      
      
      
      
      node.flags = (node.flags & ~Placement) | Hydrating;
      node = node.sibling;
    }
  } else {
    
    
    reconcileChildren(current, workInProgress, nextChildren, renderLanes);
    resetHydrationState();
  }
  return workInProgress.child;
}
function updateHostComponent(