MSDN:
bManualReset [in]
If this parameter is TRUE, the function creates a manual-reset event object, which requires the use of theResetEvent function to set the event state to nonsignaled. If this parameter is FALSE, the function creates an auto-reset event object, and system automatically resets the event state to nonsignaled after a single waiting thread has been released.
bManualReset:true, manual-reset event, 线程结束后需要手动调用ResetEvent把event变成unsignal状态。
false，auto-reset event, 线程结束后自动调用ResetEvent把event变成unsignal状态。
主要区别：调用等待事件的（诸如调用WaitForSingleObject()的线程）线程(非另起的线程)结束后需不需要手动把event变成unsignal状态
