(* * Copyright (c) 2017 - present Facebook, Inc. * All rights reserved. * * This source code is licensed under the BSD style license found in the * LICENSE file in the root directory of this source tree. An additional grant * of patent rights can be found in the PATENTS file in the same directory. *) type t val empty : t val add_int : t -> key:string -> data:int -> t val add_float : t -> key:string -> data:float -> t val add_string : t -> key:string -> data:string -> t val add_string_opt : t -> key:string -> data:string option -> t val to_json : t -> string