Function selection_convert 

pub fn selection_convert(
    widget: &impl IsA<Widget>,
    selection: &Atom,
    target: &Atom,
    time_: u32,
) -> bool

Requests the contents of a selection. When received, a “selection-received” signal will be generated.

widget

The widget which acts as requestor

selection

Which selection to get

target

Form of information desired (e.g., STRING)

time_

Time of request (usually of triggering event) In emergency, you could use GDK_CURRENT_TIME

Returns

true if requested succeeded. false if we could not process request. (e.g., there was already a request in process for this widget).