include/sendr@message_Message.hrl
-record(message, {
from :: gleam@option:option(sendr@message@mailbox:mailbox()),
reply_to :: gleam@option:option(list(sendr@message@mailbox:mailbox())),
to :: gleam@option:option(list(sendr@message@mailbox:mailbox())),
cc :: gleam@option:option(list(sendr@message@mailbox:mailbox())),
bcc :: gleam@option:option(list(sendr@message@mailbox:mailbox())),
subject :: gleam@option:option(binary()),
attachments :: list(sendr@message@attachment:attachment()),
body :: sendr@message@body:body()
}).