I tried to add the simple marker on the location with the latitude and longitude. However, the marker is not showing up on the map. The following is the code to display marker.
func addSimpleMarkerSymbol() {
let symbol = AGSSimpleMarkerSymbol(style: .diamond, color: .red, size: 28)
let point = AGSPoint(x: Double(self.longitude), y: Double(self.latitude), spatialReference: .wgs84())
let graphic = AGSGraphic(geometry: point, symbol: symbol, attributes: nil)
self.graphicsOverlay.graphics.add(graphic)
self.graphicsOverlays.add(self.graphicsOverlay)
}