gdk:drop-read-value-async (drop gtype priority cancellable func)

drop -- a gdk:drop object
gtype -- a g:type-t type ID to read
priority -- an integer with the I/O priority of the request
cancellable -- an optional g:cancellable object, nil to ignore
func -- a g:async-ready-callback callback function to call when the request is satisfied

Asynchronously request the drag operation's contents converted to the given gtype. When the operation is finished func will be called. You can then call the gdk:drop-read-value-finish function to get the resulting g:value value.

For local drag'n'drop operations that are available in the given gtype, the value will be copied directly. Otherwise, GDK will try to use the gdk:content-deserialize-async to convert the data.