package email_message
Module Octet_stream.EncodingSource
RFC 2045 MIME-encoded Bigstrings.
Text or binary are the type of the plaintext. For Base64, if the mode is text, '\n' is turned into '\r\n' when encoding, and vice versa.
Determine an encoding based on email headers. ignore_base64_for_multipart is useful because some clients can't read RFCs and incorrectly indicate a transfer encoding of base64 for multipart messages.