How can this example be added to the Assertion with itfoxtec-identity-saml2 in C#? Cant find an adequate method...

```
<saml:AttributeStatement>
<saml:Attribute FriendlyName="SurName" Name="urn:oid:2.5.4.4" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
  <saml:AttributeValue xsi:type="xs:string">Max</saml:AttributeValue>
</saml:Attribute>
<saml:Attribute FriendlyName="CommonName" Name="urn:oid:2.5.4.3" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
  <saml:AttributeValue xsi:type="xs:string">Max Mustermann</saml:AttributeValue>
</saml:Attribute>
<saml:Attribute Name="urn:oid:0.9.2342.19200300.100.1.1" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
  <saml:AttributeValue xsi:type="xs:string">has</saml:AttributeValue>
</saml:Attribute>
<saml:Attribute FriendlyName="Email" Name="urn:oid:0.9.2342.19200300.100.1.3" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
  <saml:AttributeValue xsi:type="xs:string">max@mustermann.de</saml:AttributeValue>
</saml:Attribute>  </saml:AttributeStatement>

```