You might have heard about the recent blogspot of Reverse Engineering Xiaomi’s Analytics app at https://www.thijsbroenink.com/2016/09/xiaomis-analytics-app-reverse-engineered/
Summary - Basically there is an application called Analystics which is there by default on every MIUI user's phone. This application runs in background 24*7 and it also re appears without user interaction even if you delete it.
