sync & async methods in single service contracts works normaly;
but when sync located in contract A, and async methods located in inherited contract B,
ChannelFactory throws InvalidoperationException
The synchronous OperationContract method 'DoWork' in type 'WpfApplication1.App+IBar' was matched with the asynchronous OperationContract methods 'BeginDoWork' and 'EndDoWork' because they have the same operation name 'DoWork'. When a synchronous
OperationContract method is matched to a pair of asynchronous OperationContract methods, the two OperationContracts must have the same value for the 'Action' property. In this case, the values are different. To fix it, change the 'Action property of one of
the OperationContracts to match the other. Alternatively, changing the name of one of the methods will prevent matching.