Adds one or more new key:value pairs to the given client_options.
Parameters
client_options
The client options to modify.
...
KEY, VALUE, [KEY, VALUE], NULL
Note
The keys and values passed are expected to be strings, except for the keys "ApplicationSINF", "iTunesMetadata", "ReturnAttributes" which are expecting a plist_t node as value and "SkipUninstall" expects int.