why corewcf slower than .netframework wcf

basically， .net core webapi 2x faster than .net framework webapi 。
but corewcf slower than .net framework wcf

TestDemo:

[System.ServiceModel.ServiceContract]
[CoreWCF.ServiceContract]
public interface ITest
{
[System.ServiceModel.OperationContract]
[CoreWCF.OperationContract]
string GetTest1();

}

[CoreWCF.ServiceBehavior(ConcurrencyMode = CoreWCF.ConcurrencyMode.Multiple, InstanceContextMode = CoreWCF.InstanceContextMode.Single)]

public partial class Test : ITest
{
public string GetTest1()
{
return "1234567890";
}
}