code: function emitError(currentDomain, err) {
      /*jshint camelcase: false*/
      util._extend(err, {
          domain: currentDomain,
          domain_thrown: true
      });
      currentDomain.emit('error', err);
      currentDomain.exit();
  }
docs: see https://github.com/joyent/node/blob/v0.8.8-release/lib/domain.js#L53