public interface IMutableUnionTypeDefinition : IUnionTypeDefinition, ICompositeTypeDefinition, IOutputDefinition, IMutableNamedTypeDefinition, IMutableAnnotatableDefinition, IAnnotatableDefinition, IMutableDirectiveAnnotationsDefinition, IMutableClrType, IMutableNamed, IMutableDefinition, IMutableDescription, IMutableAbstractTypeDefinition, IAbstractTypeDefinition, INamedTypeDefinition, IMemberDefinition, IDescription, INamedTypeReference, IGraphQLTypeReference, INamed, IDirectiveAnnotations, IDirectiveAnnotationsDefinition, IClrType, IMutableMemberTypesDefinition, IMemberTypesDefinition