One 
      
       TOD
      
       Cal
      primaryFibers.delete(primaryFiber);
      return;
    }
    const id = getFiberID(primaryFiber);
    if (isRoot) {
       Roo
       So 
      pendingUnmountedRootID = id;
    } else if (!shouldFilterFiber(fiber)) {
       To 
       we'
       and 
      if (isSimulated) {
        pendingSimulatedUnmountedIDs.push(id);
      } else {
        pendingRealUnmountedIDs.push(id);
      }
    }
    fiberToIDMap.delete(primaryFiber);
    idToFiberMap.delete(id);
    primaryFibers.delete(primaryFiber);
    const isProfilingSupported = fiber.hasOwnProperty('treeBaseDuration');
    if (isProfilingSupported) {
      idToRootMap.delete(id);
      idToTreeBaseDurationMap.delete(id);