(Regarding the experimental `React.unstable_Profiler` API and reactjs/rfcs/pull/51.)

PR #13058 changed the behavior of React profiling builds to opt host roots into `ProfileMode` if the React DevTools extension is detected. This was necessary in order to have accurate tree base time measurements for the visual flame graphs.

The Profiler plug-in for DevTools does feature detection to determine if it's enabled by looking at each root and seeing if any of the fibers contain an `actualDuration` attribute,

The problem is that the `actualDuration` attribute will be present on v16.4 fibers, which pre-date PR #13058. As a result, the Profiler UI may enable itself with versions of React that it cannot work correctly with.

Perhaps an easy solution would be to rename one of the `unstable_Profiler`'s fiber attributes prior to the next minor release (e.g. `treeBaseTime` -> `treeBaseDuration`) and change the DevTools Profiler to feature check using this new name instead.
if (didError) {
      invariant(
        nextEffect !== null,
        'Should have next effect. This error is likely caused by a bug ' +
          'in React. Please file an issue.',
      );
      captureCommitPhaseError(nextEffect, error);
      
      if (nextEffect !== null) {
        nextEffect = nextEffect.nextEffect;
      }
    }
  }
  stopCommitHostEffectsTimer();
  resetAfterCommit(root.containerInfo);
  
  
  
  
  root.current = finishedWork;
  
  
  
  
  nextEffect = firstEffect;
  startCommitLifeCyclesTimer();
  while (nextEffect !== null) {
    let didError = false;
    let error;
    if (__DEV__) {