Creating a Simple MIME Part
This section describes the process for creating a simple MIME part that can also be transmitted as a standalone message.
A MIME part that contains simple data (rather than another MIME part) is the basic building block of the MIME format. Even the most complicated MIME message boils down to a collection of simple MIME parts. Since the MIME specification defines a MIME message as any MIME part that contains a MIME-Version header, the procedure in this section applies equally to creating a MIME part.
To create a simple MIME message: