module Encoder: sig .. end
val w_unstructured : (MrMime_header.unstructured,
        ([> `Partial of Bytes.t * int * int * (int -> 'a) ] as 'a) Encoder.partial)
       Wrap.k1
val w_field : ([ `Bcc of Rfc5322.address list
        | `Cc of Rfc5322.address list
        | `Comments of Rfc5322.unstructured
        | `Date of Rfc5322.date
        | `Field of string * Rfc5322.unstructured
        | `From of Rfc5322.mailbox list
        | `InReplyTo of Rfc5322.phrase_or_msg_id list
        | `Keywords of Rfc5322.phrase list
        | `MessageID of Rfc822.msg_id
        | `References of Rfc5322.phrase_or_msg_id list
        | `ReplyTo of Rfc5322.address list
        | `Sender of Rfc5322.mailbox
        | `Skip of string
        | `Subject of Rfc5322.unstructured
        | `To of Rfc5322.address list
        | `Unsafe of string * Rfc5322.unstructured ],
        ([> `Partial of Bytes.t * int * int * (int -> 'a) ] as 'a) Encoder.partial)
       Encoder.k1
 : (MrMime_header.header,
        ([> `Partial of Bytes.t * int * int * (int -> 'a) ] as 'a) Encoder.partial)
       Encoder.k1