/*
 * call-seq:
 *   read
 *
 * Move the Reader forward through the XML document.
 */
static VALUE read_more(VALUE self)
{
  xmlTextReaderPtr reader;
  Data_Get_Struct(self, xmlTextReader, reader);

  int ret = xmlTextReaderRead(reader);
  if(ret == 1) return self;
  if(ret == 0) return Qnil;

  rb_raise(rb_eRuntimeError, "Error pulling: %d", ret);
}