[备忘]解决ManualResetEvent.WaitOne在Silverlight环境下将整个UI线程卡死，并无法继续调用异步子线程的问题

Synchronous Web Service Calls with Silverlight: Dispelling the async-only myth:

http://www.codeproject.com/KB/silverlight/SynchronousSilverlight.aspx

Making Silverlight Emulate Synchronous Requests:
http://www.eggheadcafe.com/tutorials/aspnet/91f69224-3da5-4959-9901-c5c717c9b184/making-silverlight-emulat.aspx