Op.ReadFile reads.
val v_op : id:id -> mark:mark -> created:B00_std.Time.span -> ?post_exec:(op -> unit) -> ?k:(op -> unit) -> B00_std.Fpath.t -> opv_op declares a file read operation, see the corresponding accessors for the semantics of the various arguments.
val v : file:B00_std.Fpath.t -> data:string -> tv constructs a bare read operation.
val file : t -> B00_std.Fpath.tfile r is the file read by r.
val data : t -> stringdata r is the read data.
val set_data : t -> string -> unitset_data r d sets the read data to d.
val discard_data : t -> unitdiscard_data () discards read data.