Asynchronously request the @clipboard contents converted to the given
@type.
When the operation is finished @callback will be called. You must then call
[method@Gdk.Clipboard.read_value_finish] to get the resulting GValue.
For local clipboard contents that are available in the given GType,
the value will be copied directly. Otherwise, GDK will try to use
[func@content_deserialize_async] to convert the clipboard's data.
Asynchronously request the @clipboard contents converted to the given @type.
When the operation is finished @callback will be called. You must then call [method@Gdk.Clipboard.read_value_finish] to get the resulting GValue.
For local clipboard contents that are available in the given GType, the value will be copied directly. Otherwise, GDK will try to use [func@content_deserialize_async] to convert the clipboard's data.