type t
include sig ... end
val sexp_of_t : t ‑> Base.Sexp.t
val multipart_boundary : t ‑> Email_message__.Boundary.t option
val is_multipart : t ‑> bool
val is_message_rfc822 : t ‑> bool
val last : Email_message__.Headers.t ‑> t option
val default : parent:t option ‑> t