Batteries user guide : BatStream.StreamLabels

`sig
val iter : f:('a -> unit) -> 'a BatStream.t -> unit
val to_string_fmt :
fmt:('a -> string, unit, string) Pervasives.format ->
'a BatStream.t -> string
val to_string_fun : fn:('a -> string) -> 'a BatStream.t -> string
val foldl :
f:('a -> 'b -> 'a * bool option) -> init:'a -> 'b BatStream.t -> 'a
val foldr : f:('a -> 'b lazy_t -> 'b) -> init:'b -> 'a BatStream.t -> 'b
val fold : f:('a -> 'a -> 'a * bool option) -> init:'a BatStream.t -> 'a
val filter : f:('a -> bool) -> 'a BatStream.t -> 'a BatStream.t
val map : f:('a -> 'b) -> 'a BatStream.t -> 'b BatStream.t
val map2 :
f:('a -> 'b -> 'c) -> 'a BatStream.t -> 'b BatStream.t -> 'c BatStream.t
val scanl : f:('a -> 'b -> 'a) -> 'a -> 'b BatStream.t -> 'a BatStream.t
val scan : f:('a -> 'a -> 'a) -> 'a BatStream.t -> 'a BatStream.t
val take_while : f:('a -> bool) -> 'a BatStream.t -> 'a BatStream.t
val drop_while : f:('a -> bool) -> 'a BatStream.t -> 'a BatStream.t
val merge :
f:(bool -> 'a -> bool) ->
'a BatStream.t * 'a BatStream.t -> 'a BatStream.t
val switch :
f:('a -> bool) -> 'a BatStream.t -> 'a BatStream.t * 'a BatStream.t
end`