<PackageReference Include="System.ServiceModel.Primitives" Version="6.2.0" />

System.ServiceModel.MessageDictionary

namespace System.ServiceModel { internal class MessageDictionary { public XmlDictionaryString MustUnderstand; public XmlDictionaryString Envelope; public XmlDictionaryString Header; public XmlDictionaryString Body; public XmlDictionaryString Prefix; public XmlDictionaryString Fault; public XmlDictionaryString MustUnderstandFault; public XmlDictionaryString Namespace; public MessageDictionary(ServiceModelDictionary dictionary); } }