`type t``= Async_smtp_types__.Envelope_bodiless.t Async_smtp_types__.Routed.t```
`include sig ... end`
`val sexp_of_t : t ‑> Base.Sexp.t`
`include Async_smtp_types__.Envelope_container.With_headers with type t := t`
`type t`````
`val headers : t ‑> Email_message.Email_headers.t`
`val last_header : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> Email_message.Email_headers.Name.t ‑> Email_message.Email_headers.Value.t option`
`val find_all_headers : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> Email_message.Email_headers.Name.t ‑> Email_message.Email_headers.Value.t list`
`val add_header : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> name:string ‑> value:string ‑> t`
`val add_headers : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> (string * string) list ‑> t`
`val set_header : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> name:string ‑> value:string ‑> t`
`val add_header_at_bottom : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> name:string ‑> value:string ‑> t`
`val add_headers_at_bottom : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> (string * string) list ‑> t`
`val set_headers : t ‑> Email_message.Email_headers.t ‑> t`
`val set_header_at_bottom : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> name:string ‑> value:string ‑> t`
`val smash_and_add_header : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> name:string ‑> value:string ‑> t`
`val modify_headers : t ‑> f:(Email_message.Email_headers.t ‑> Email_message.Email_headers.t) ‑> t`
`val filter_headers : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> f:(name:Email_message.Email_headers.Name.t ‑> value:Email_message.Email_headers.Value.t ‑> bool) ‑> t`
`val map_headers : ?⁠whitespace:Email_message.Email_headers.Whitespace.t ‑> t ‑> f:(name:Email_message.Email_headers.Name.t ‑> value:Email_message.Email_headers.Value.t ‑> string) ‑> t`
`include Async_smtp_types__.Envelope_container.With_info with type t := t`
`type t`````
`type envelope_info`````
`val sender : t ‑> Async_smtp_types__.Sender.t`
`val sender_args : t ‑> Async_smtp_types__.Sender_argument.t list`
`val string_sender : t ‑> string`
`val recipients : t ‑> Email_message.Email_address.t list`
`val rejected_recipients : t ‑> Email_message.Email_address.t list`
`val string_recipients : t ‑> string list`
`val route : t ‑> string option`
`val id : t ‑> Async_smtp_types__.Envelope_id.t`
`val info : t ‑> envelope_info`
`val next_hop_choices : t ‑> Async_smtp_types__.Socket_address.t list`
`val retry_intervals : t ‑> Async_smtp_types__.Retry_interval.t list`
`val envelope_bodiless : t ‑> Async_smtp_types__.Envelope_bodiless.t`
`val envelope_info : t ‑> Async_smtp_types__.Envelope_info.t`
`val headers : t ‑> Email_message.Email_headers.t`
`val create : Async_smtp_types__.Envelope_bodiless.t Async_smtp_types__.Routed.create`
`val set : (?⁠headers:Email_message.Email_headers.t ‑> t ‑> unit ‑> t) Async_smtp_types__.Routed.set`