use "encode/base64"
class val MIMEContentTypeApplication is MIMEContentType
var texttype: String val
var filename: (None | String val) = None
new val create(texttype': String val = "binary", filename': (String val | None) = None) =>
texttype = texttype'
filename = filename'
fun content_type(): String val =>
"Content-Type: application/" + texttype + "\r\n"
fun content_disposition(): String val =>
match filename
| let name: None => return ""
| let name: String val => return "Content-Disposition: attachment; filename=" + name + "\r\n"
end
""