private void reset() {
        mUserLast = 0;
        mSystemLast = 0;
        mIdleLast = 0;
        mIoWaitLast = 0;
        mTotalLast = 0;
        mAppCpuTimeLast = 0;
    }
Get cpu rate information

@return string show cpu rate information
blockcanary-analyzer/src/main/java/com/github/moduth/blockcanary/CpuSampler.java