module BytesLabels: sig .. endlet length: bytes => int;
let get: (bytes, int) => char;
get s n returns the byte at index n in argument s.
    Raise Invalid_argument if n not a valid index in s.
let set: (bytes, int, char) => unit;
set s n c modifies s in place, replacing the byte at index n
    with c.
    Raise Invalid_argument if n is not a valid index in s.
let create: int => bytes;
create n returns a new byte sequence of length n. The
    sequence is uninitialized and contains arbitrary bytes.
    Raise Invalid_argument if n < 0 or n > Sys.max_string_length.
let make: (int, char) => bytes;
make n c returns a new byte sequence of length n, filled with
    the byte c.
    Raise Invalid_argument if n < 0 or n > Sys.max_string_length.
let init: (int, ~f: int => char) => bytes;
init n f returns a fresh byte sequence of length n,
    with character i initialized to the result of f i.
    Raise Invalid_argument if n < 0 or n > Sys.max_string_length.
let empty: bytes;
let copy: bytes => bytes;
let of_string: string => bytes;
let to_string: bytes => string;
let sub: (bytes, ~pos: int, ~len: int) => bytes;
sub s start len returns a new byte sequence of length len,
    containing the subsequence of s that starts at position start
    and has length len.
    Raise Invalid_argument if start and len do not designate a
    valid range of s.
let sub_string: (bytes, int, int) => string;
sub but return a string instead of a byte sequence.let fill: (bytes, ~pos: int, ~len: int, char) => unit;
fill s start len c modifies s in place, replacing len
    characters with c, starting at start.
    Raise Invalid_argument if start and len do not designate a
    valid range of s.
let blit:
  (~src: bytes, ~src_pos: int, ~dst: bytes, ~dst_pos: int, ~len: int) => unit;
blit src srcoff dst dstoff len copies len bytes from sequence
    src, starting at index srcoff, to sequence dst, starting at
    index dstoff. It works correctly even if src and dst are the
    same byte sequence, and the source and destination intervals
    overlap.
    Raise Invalid_argument if srcoff and len do not
    designate a valid range of src, or if dstoff and len
    do not designate a valid range of dst.
let concat: (~sep: bytes, list(bytes)) => bytes;
concat sep sl concatenates the list of byte sequences sl,
    inserting the separator byte sequence sep between each, and
    returns the result as a new byte sequence.let iter: (~f: char => unit, bytes) => unit;
iter f s applies function f in turn to all the bytes of s.
    It is equivalent to f (get s 0); f (get s 1); ...; f (get s
    (length s - 1)); ().let iteri: (~f: (int, char) => unit, bytes) => unit;
Bytes.iter, but the function is applied to the index of
    the byte as first argument and the byte itself as second
    argument.let map: (~f: char => char, bytes) => bytes;
map f s applies function f in turn to all the bytes of s and
    stores the resulting bytes in a new sequence that is returned as
    the result.let mapi: (~f: (int, char) => char, bytes) => bytes;
mapi f s calls f with each character of s and its
    index (in increasing index order) and stores the resulting bytes
    in a new sequence that is returned as the result.let trim: bytes => bytes;
' ', '\012', '\n', '\r', and '\t'.let escaped: bytes => bytes;
let index: (bytes, char) => int;
index s c returns the index of the first occurrence of byte c
    in s.
    Raise Not_found if c does not occur in s.
let rindex: (bytes, char) => int;
rindex s c returns the index of the last occurrence of byte c
    in s.
    Raise Not_found if c does not occur in s.
let index_from: (bytes, int, char) => int;
index_from s i c returns the index of the first occurrence of
    byte c in s after position i.  Bytes.index s c is
    equivalent to Bytes.index_from s 0 c.
    Raise Invalid_argument if i is not a valid position in s.
    Raise Not_found if c does not occur in s after position i.
let rindex_from: (bytes, int, char) => int;
rindex_from s i c returns the index of the last occurrence of
    byte c in s before position i+1.  rindex s c is equivalent
    to rindex_from s (Bytes.length s - 1) c.
    Raise Invalid_argument if i+1 is not a valid position in s.
    Raise Not_found if c does not occur in s before position i+1.
let contains: (bytes, char) => bool;
contains s c tests if byte c appears in s.let contains_from: (bytes, int, char) => bool;
contains_from s start c tests if byte c appears in s after
    position start.  contains s c is equivalent to contains_from
    s 0 c.
    Raise Invalid_argument if start is not a valid position in s.
let rcontains_from: (bytes, int, char) => bool;
rcontains_from s stop c tests if byte c appears in s before
    position stop+1.
    Raise Invalid_argument if stop < 0 or stop+1 is not a valid
    position in s.
let uppercase: bytes => bytes;
let lowercase: bytes => bytes;
let capitalize: bytes => bytes;
let uncapitalize: bytes => bytes;
type t = bytes;
let compare: (t, t) => int;
Pervasives.compare.  Along with the type t,
    this function compare allows the module Bytes to be passed as
    argument to the functors Set.Make and Map.Make.