Function add_parts

async fn add_parts(
    context: &Context,
    mime_parser: &mut MimeMessage,
    imf_raw: &[u8],
    to_ids: &[ContactId],
    rfc724_mid: &str,
    from_id: ContactId,
    seen: bool,
    is_partial_download: Option<u32>,
    replace_msg_id: Option<MsgId>,
    fetching_existing_messages: bool,
    prevent_rename: bool,
    verified_encryption: VerifiedEncryption,
) -> Result<ReceivedMsg>

Creates a ReceivedMsg from given parts which might consist of multiple messages (if there are multiple attachments). Every entry in mime_parser.parts produces a new row in the msgs table.