Requests the contents of a selection.
When received, a “selection-received” signal will be generated.
The widget which acts as requestor
Which selection to get
Form of information desired (e.g., STRING)
Time of request (usually of triggering event) In emergency, you could use CURRENT_TIME
true if requested succeeded. false if we could not process request. (e.g., there was already a request in process for this widget).