.Address: ClassType

.Group: ClassType

.BaseHeader: ClassType

.UnstructuredHeader: ClassType

.UniqueUnstructuredHeader: ClassType
.UniqueUnstructuredHeader <: .UnstructuredHeader

.DateHeader: ClassType

.AddressHeader: ClassType

.UniqueAddressHeader: ClassType
.UniqueAddressHeader <: .AddressHeader

.SingleAddressHeader: ClassType
.SingleAddressHeader <: .AddressHeader

.UniqueSingleAddressHeader: ClassType
.UniqueSingleAddressHeader <: .SingleAddressHeader

.MIMEVersionHeader: ClassType

.ParameterizedMIMEHeader: ClassType

.ContentTypeHeader: ClassType
.ContentTypeHeader <: .ParameterizedMIMEHeader

.ContentDispositionHeader: ClassType
.ContentDispositionHeader <: .ParameterizedMIMEHeader

.ContentTransferEncodingHeader: ClassType

.MessageIDHeader: ClassType

.Headerregistry: ClassType