718 turbo cooling

Can anyone provide a somewhat technical explaination of how the turbo bearings are kept cool, especially after a hard run? There must be some electric pump for oil that works once the engine shuts off (start/stop feature would necessitate this I would think). I had a few older turbo cars and always heard horror stories about hot turbo bearings baking oil because of the high heat. Turbos must have evolved and I have read about extra coolant passages in some turbo set ups while others circulate oil via an electric pump once the engine is shut down. Of course I'll cool down my 718 after each drive, once I get it next week ?, but would like to know what is happening behind the scenes.