#I9GV06:[新需求]: 支持采样主线程调用栈
Class ThreadSampler:
Init():Init Sampler, include record buffer and unwinder, register signal.
Sample():Interface of Sample, to send sample request.
CollectStack(string, bool):collect stack info into string, stack info can be formed into tree format or not by the second parameter.
InvalidateCache():Release Sampler, include unwinder and record buffer.