doc; relax some types

src/core/in_buf.mli

@@ -6,8 +6,10 @@ class type t =
     inherit In.t
 
     method fill_buf : unit -> Slice.t
-    (** returns a slice into the [bic]'s internal buffer,
-        and ensures it's empty only if [bic.ic] is empty. *)
+    (** [ic#fill_buf()] returns a slice into the [ic]'s internal buffer,
+        and ensures it's empty only if [ic.ic] is empty. In other
+        words, the invariant is that this only returns
+        an empty slice if the input stream is exhausted. *)
 
     method consume : int -> unit
     (** Consume [n] bytes from the inner buffer. This is only

src/core/out_buf.mli

@@ -35,7 +35,9 @@ class dummy : t
 val dummy : t
 (** Dummy output, drops everything written to it. *)
 
-(** Make a bufferized output from a non bufferized output+close *)
+(** Make a bufferized output from a non bufferized output+close.
+ @param bytes the buffer to use. It's owned by this channel as long
+ as the channel exists. *)
 class virtual t_from_output :
   ?bytes:bytes
   -> unit
@@ -50,9 +52,9 @@ class virtual t_from_output :
         flush and then call this. *)
      end
 
-class bufferized : ?bytes:bytes -> Out.t -> t
+class bufferized : ?bytes:bytes -> #Out.t -> t
 
-val bufferized : ?bytes:bytes -> Out.t -> t
+val bufferized : ?bytes:bytes -> #Out.t -> t
 
 class of_out_channel : ?close_noerr:bool -> out_channel -> t_seekable