Modify xmlAttribute Name like xsi:type

I am created class for Response. Class name is TestResponse. I need to add attribute xsi:type="xsd:Boolean" like that.

But i cant give that attribute name is "xsi:type".

I need any guidance to add xsi before type tag.

Class:

[DataContract(Namespace = "urn:test:datacontracts")]
public class TestResponse
{  
        private Date _date;
        public Date data
        {
            get { return _date; }
            set { _date = value; }
        }   
        [DataContract]
        public class Date
        {
            [DataMember, XmlAttribute]
            public string type = "xsd:boolean";

            [DataMember, XmlText]
            public Boolean data;
        }
}

My Response:

<TestResponse>
         <cancelResult>
                <data type="xsd:boolean">false</data>
         </cancelResult>
      </TestResponse>

Expected Response

<TestResponse>
       <data xsi:type="xsd:boolean">false</data>
</TestResponse>