header

const (
	MIMEVersion             = "MIME-Version"
	ContentID               = "Content-ID"
	ContentType             = "Content-Type"
	ContentDescription      = "Content-Description"
	ContentDisposition      = "Content-Disposition"
	ContentTransferEncoding = "Content-Transfer-Encoding"
	From                    = "From"
	To                      = "To"
	Subject                 = "Subject"
	Date                    = "Date"
	ListID                  = "List-Id"
	ListOwner               = "List-Owner"
	ListPost                = "List-Post"
	ListHelp                = "List-Help"
	ListUnsubscribe         = "List-Unsubscribe"

	// If multiple URLs are present in List-Unsubscribe, the inbox provider will apply the List-Unsubscribe-Post command to the first HTTPS URI it finds. (RFC 8058)
	ListUnsubscribePost = "List-Unsubscribe-Post"
)