如何为每个WCF调用添加自定义HTTP标头？

I have a WCF service that is hosted in a Windows Service. Clients that using this service must pass an identifier every time they're calling service methods (because that identifier is important for what the called method should do). I thought it is a good idea to somehow put this identifier to the WCF header information.I have a WCF service that is hosted in a Window