Use point symbology with a feature layer in Leaflet/Esri-Leaflet

featureLayerSymbology.js

var iconFs = L.icon({
    iconUrl: 'http://services.arcgis.com/SgB3dZDkkUxpEHxu/ArcGIS/rest/services/huc17_accesses/FeatureServer/0/images/d66f4bf18356e409c6221a46633b935a',
    iconSize: [14, 15],
    iconAnchor: [0, 0]
});

var layer = L.esri.featureLayer('http://services.arcgis.com/SgB3dZDkkUxpEHxu/arcgis/rest/services/huc17_accesses/FeatureServer/0', {
    pointToLayer: function (feature, latlng) {
        return L.marker(latlng, { icon:  conFs} );
    }
});