sig
  type t =
      Did_not_reach_eof_for of Core.Std.Time.Span.t
    | Reached_eof
    | Delayed_due_to_null_reads_for of Core.Std.Time.Span.t
    | No_longer_delayed_due_to_null_reads
  val to_string_hum : File_tail.Warning.t -> string
  val sexp_of_t : File_tail.Warning.t -> Sexplib.Sexp.t
end