Fixed WSF_RESPONSE chunk transfer implementation

and also the optional extension `a_ext' should now include the ';'
Now HTTP_HEADER is an ITERABLE [READABLE_STRING_8]

library/network/protocol/http/src/http_header.e

@@ -22,7 +22,7 @@ class
 	HTTP_HEADER
 
 inherit
-	ANY
+	ITERABLE [READABLE_STRING_8]
 
 create
 	make,
@@ -149,6 +149,14 @@ feature -- Access
 			Result := res
 		end
 
+feature -- Access
+
+	new_cursor: INDEXABLE_ITERATION_CURSOR [READABLE_STRING_8]
+			-- Fresh cursor associated with current structure
+		do
+			Result := headers.new_cursor
+		end
+
 feature -- Header: filling
 
 	append_array (a_headers: ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])