/// This type does not implement `MessageValue`, as serialized messages of this value cannot be created (from `Message::serialize()`), nor deserialized. They must first be converted into a typed `SerializedMessage<V>` with `UntypedSerializedMessage::into_typed<V>()`.
/// Transmute into a specifically typed `SerializedMessage`
///
/// # Safety
/// If `V` is not the original type of this message (before being untyped), then deserialisation will likely fail, or, much worse, cause a *type consufion* bug, where the object of type `V` is successfully deserialized with an invalid value from an unknown type.