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-# perf_counter (v2.2.1)
+# perf_counter (v2.2.2-dev)
 A dedicated performance counter for Cortex-M Systick. It shares the SysTick with users' original SysTick function(s) without interfering with it. This library will bring new functionalities, such as performance counter,` delay_us` and `clock()` service defined in `time.h`.
 
 ### Features: