- Parse List-Post value like List-Unsubscribe: comma separated angle bracket limited list of <mailto:> or <url> values
- Check if List-Archive value is angle bracket delimited
fetch BODYSTRUCTURE along with ENVELOPE from server and set
has_attachments based on the MIME structure of the envelope.
Notes: BODYSTRUCTURE returns the MIME structure of the envelope without
the data, so if it includes a multipart/mixed it *should* have
attachments.
ENVELOPE returns basic headers of the message like Sender, Subject, Date
etc.
At a certain point when expecting a line terminator parts() checks for
'\n' but not '\r\n'. This resulted in all multipart attachments coming
from b"\r\n" sources like IMAP having only one part when parsed.
Attachment needs to know the range of bytes where the body part of the
attachment is located. The Attachment.raw field contains the entire
attachment, headers and body. The new Attachment.body fields contains a
`StrBuilder` which contains the offset and length of the body part inside
`raw`.
'\n'
when an empty header is last, the rest of the body keeps getting parsed
as headers. when header starts with '\n' because the value is long, the
value gets parsed as a name and the header parser fails.
closes#100closes#101closes#122