write_header_tag Subroutine

   subroutine write_header_tag(self)
   !< Write header tag.
   class(xml_writer_abstract), intent(inout) :: self   !< Writer.
   type(string)                              :: buffer !< Buffer string.

   buffer = '<?xml version="1.0"?>'//end_rec
   if (endian==endianL) then
      buffer = buffer//'<VTKFile type="'//self%topology//'" version="1.0" byte_order="LittleEndian">'
   else
      buffer = buffer//'<VTKFile type="'//self%topology//'" version="1.0" byte_order="BigEndian">'
   endif
   if (.not.self%is_volatile) then
      write(unit=self%xml, iostat=self%error)buffer//end_rec
   else
      self%xml_volatile = self%xml_volatile//buffer//end_rec
   endif
   self%indent = 2
   endsubroutine write_header_tag