Data devices glue data sources and offers together. A data device is associated with a wl_seat and is obtained by the clients using the wl_data_device_manager factory object, which is also responsible for creating data sources.
Clients are informed of new data offers through the wl_data_device.data_offer event. After this event is generated the data offer will advertise the available mime types. New data offers are introduced prior to their use for selection or drag and drop.
Each data device has a selection data source. Clients create a data source object using the device manager and may set it as the current selection for a given data device. Whenever the current selection changes, the client with keyboard focus receives a wl_data_device.selection event. This event is also generated on a client immediately before it receives keyboard focus.
The data offer is introduced with wl_data_device.data_offer event before the selection event.
