(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.
case ClassComponent:
        popLegacyContextProvider(failedUnitOfWork);
        break;
      case HostPortal:
        popHostContainer(failedUnitOfWork);
        break;
      case ContextProvider:
        popProvider(failedUnitOfWork);
        break;
    }
    
    isReplayingFailedUnitOfWork = true;
    originalReplayError = thrownValue;
    invokeGuardedCallback(null, workLoop, null, isYieldy);
    isReplayingFailedUnitOfWork = false;
    originalReplayError = null;
    if (hasCaughtError()) {
      clearCaughtError();
      if (enableProfilerTimer) {
        if (failedUnitOfWork.mode & ProfileMode) {
          recordElapsedActualRenderTime(failedUnitOfWork);
        }
        
        stopBaseRenderTimerIfRunning();
      }
    } else {
      
      
      nextUnitOfWork = failedUnitOfWork;
    }