SourceClient specialization for showing the content of the root of a media source's browsing hierarchy. It provides access to a source's categories (the top-level items used to access all available content), and can be instructed to browse through any of the available content.
If no custom media item is initially browsed to via browseTo, the contents of the first available category will be made available automatically.
ID of the source to connect to.
Load and subscribe to a new media item. The mediaItem will first be updated with the newMediaItem, then the contents will be updated with its child items. It is not necessary for the client to be connected already. This method can be called on creation to initially browse to the specified newMediaItem instead of the default.