code: protected static void visit(VirtualFile file, VirtualFileVisitor visitor) throws IOException {
          if (file == null) {
              throw VFSMessages.MESSAGES.nullArgument("file");
          }
          visitor.visit(file);
      }
docs: Visit the virtual file system
  
  @param file    the file
  @param visitor the visitor
  @throws IOException              for any problem accessing the VFS
  @throws IllegalArgumentException if the file or visitor is null