Optional. 255 character string of data that you can add for bookkeeping purposes. You can read this back as part of the request object.

Optional. This controls what sets of friends get shown if a friend selector is shown. The different sets are selectable in a selector. The value is a list of filters for friends to show. Filters are selectable by the user using a selector in the dialog. A built-in filter is expressed as a string 'all', 'app_users', or 'app_non_users'. Respectively, these denote all friends, friends who use the application, and friends who don't. Custom filters are expressed as dictionaries with a 'name' key and a 'user_ids' key, which respectively have values that are a string and a list of user ids. 'name' is the name of the custom filter that will show in the selector. 'user_ids' is the list of friends to include, in the order in which they are to appear. Default value is '', which has the same effect as ['all', 'app_users', 'app_non_users'].

The message the receiving user will see. It appears as a question posed by the sending user. The maximum length is 255 characters.

Optional. The title for the friend selector dialog. Maximum length is 50 characters.

A comma-separated list containing user IDs or usernames. If this is specified, the user will not have a choice of recipients. If this is omitted, the user will see a friend selector.