【WSAEvent】
1、WSACreateEvent。创建WSA事件。
2、WSAEventSelect。
lNetworkEvents [in]
A bitmask that specifies the combination of FD_XXX network events in which the application has interest.
0表示成功。
参考：https://msdn.microsoft.com/en-us/library/ms741576(VS.85).aspx
3、WSAWaitForMultipleEvents。
The WSAWaitForMultipleEvents function returns when one or all of the specified event objects are in the signaled state, when the time-out interval expires, or when an I/O completion routine has executed.
参考：https://msdn.microsoft.com/en-us/library/ms742219(v=vs.85).aspx
4、WSAEnumNetworkEvents。
The WSAEnumNetworkEvents function discovers occurrences of network events for the indicated socket, clear internal network event records, and reset event objects (optional).
链接：https://msdn.microsoft.com/en-us/library/windows/desktop/ms741572(v=vs.85).aspx
