See #17798
C
     w
    const isProfilingSupported = root.memoizedInteractions != null;
    if (isProfiling && isProfilingSupported) {
       I
       T
      currentCommitProfilingMetadata = {
        changeDescriptions: recordChangeDescriptions ? new Map() : null,
        durations: [],
        commitTime: getCurrentTime() - profilingStartTime,
        interactions: Array.from(root.memoizedInteractions).map(
          (interaction: Interaction) => ({
            ...interaction,
            timestamp: interaction.timestamp - profilingStartTime,
          }),
        ),
        maxActualDuration: 0,
        priorityLevel:
          priorityLevel == null ? null : formatPriorityLevel(priorityLevel),
      };
    }
    if (alternate) {
       T
      const wasMounted =
        alternate.memoizedState != null &&
        alternate.memoizedState.element != null;
      const isMounted =
        current.memoizedState != null && current.memoizedState.element != null;
      if (!wasMounted && isMounted) {
         M