Misc.LongString
let create: int => t;
let length: t => int;
let get: t => int => char;
let set: t => int => char => unit;
let blit_string: string => int => t => int => int => unit;
let output: out_channel => t => int => int => unit;
let input_bytes_into: t => in_channel => int => unit;
let input_bytes: in_channel => int => t;