This service extension should return the target refresh rate for the device (e.g. 60, 90, 120). Calling this service extension for MacOS currently returns 0.0, and we are defaulting to 60 FPS for the parts of our tools that use this data (IntelliJ performance window, DevTools timeline).
An implementation for this would be similar to flutter/engine@4c4c999 or flutter/engine@2bd75ae