GrpcPreconditions.CheckArgument(channelCredentials.IsComposable,"Supplied channel credentials do not allow composition.");
if(!channelCredentials.IsComposable)
{
thrownewArgumentException(string.Format("{0} credentials can't be used with CallCredentials. Secure credentials like SslCredentials must be used.",channelCredentials.GetType().Name));
Assert.AreEqual("FakeChannelCredentials credentials can't be used with CallCredentials. Secure credentials like SslCredentials must be used.",ex.Message);