docs: def register_class(klass, alias=None):
      """
      Registers a class to be used in the data streaming. This is the equivalent
      to the C{[RemoteClass(alias="foobar")]} AS3 metatag.
  
      @return: The registered L{ClassAlias} instance.
      @see: L{unregister_class}
      """
      meta = util.get_class_meta(klass)
  
      if alias is not None:
          meta['alias'] = alias
  
      alias_klass = util.get_class_alias(klass) or ClassAlias
  
      x = alias_klass(klass, defer=True, **meta)
  
      if not x.anonymous:
          CLASS_CACHE[x.alias] = x
  
      CLASS_CACHE[klass] = x
  
      return x