glib/connect.go
func (v *Object) Connect(detailedSignal string, f interface{}, userData ...interface{}) (SignalHandle, error) {
	return v.connectClosure(false, detailedSignal, f, userData...)
}
func (v *Object) Connect(detailedSignal string, f interface{}, userData ...interface{}) (SignalHandle, error) {
	return v.connectClosure(false, detailedSignal, f, userData...)
}
// Connect is a wrapper around g_signal_connect_closure().  f must be
// a function with a signaure matching the callback signature for
// detailedSignal.  userData must either 0 or 1 elements which can
// be optionally passed to f.  If f takes less arguments than it is
// passed from the GLib runtime, the extra arguments are ignored.
//
// Arguments for f must be a matching Go equivalent type for the
// C callback, or an interface type which the value may be packed in.
// If the type is not suitable, a runtime panic will occur when the
// signal is emitted.