Devtool
We cannot view the (computed) metrics of devtool because of the following reasons.
- We disabled the timing report (which takes several milliseconds on my testing device), so DevTool has no data source.
 - DevTool does not understand our scheme perfectly, so it has the wrong timing data even if it is enabled.
 - It is inaccurate. Please see https://github.com/flutter/devtools/issues/4522 and this pitfall for details.
 
Instead, please use the methods discussed in previous sections to see the FPS.