如何在agm-map的特定位置显示自定义DOM元素

// 创建自定义的OverlayView类
function CustomOverlay(position, map) {
  this.position = position;
  this.map = map;
  this.div = null;
  this.setMap(map);
}

// 继承OverlayView类
CustomOverlay.prototype = new google.maps.OverlayView();

// 实现onAdd方法
CustomOverlay.prototype.onAdd = function() {
  var div = document.createElement('div');
  div.style.position = 'absolute';
  div.style.width = '100px';
  div.style.height = '100px';
  div.style.backgroundColor = 'red';
  div.innerHTML = 'Custom Element';
  this.div = div;
  var panes = this.getPanes();
  panes.overlayLayer.appendChild(div);
};

// 实现draw方法
CustomOverlay.prototype.draw = function() {
  var overlayProjection = this.getProjection();
  var position = overlayProjection.fromLatLngToDivPixel(this.position);
  var div = this.div;
  div.style.left = position.x + 'px';
  div.style.top = position.y + 'px';
};

// 实现onRemove方法
CustomOverlay.prototype.onRemove = function() {
  this.div.parentNode.removeChild(this.div);
  this.div = null;
};

// 创建地图
var map = new google.maps.Map(document.getElementById('map'), {
  center: {lat: 37.7749, lng: -122.4194},
  zoom: 12
});

// 创建自定义OverlayView实例
var customOverlay = new CustomOverlay(
  new google.maps.LatLng(37.7749, -122.4194),
  map
);