Android 支持近乎实时的推送通知吗

Android 支持近乎实时的推送通知吗？

java
// 在应用的主活动中获取设备令牌
FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(new OnSuccessListener() {
    @Override
    public void onSuccess(InstanceIdResult instanceIdResult) {
        String token = instanceIdResult.getToken();
        // 将设备令牌保存到后台服务器
    }
});
// 后台服务器发送消息
String serverKey = "YOUR_SERVER_KEY";
String deviceToken = "TARGET_DEVICE_TOKEN";
String title = "Notification Title";
String message = "Notification Message";
JSONObject jsonBody = new JSONObject();
jsonBody.put("to", deviceToken);
jsonBody.put("notification", new JSONObject()
        .put("title", title)
        .put("body", message));
String requestBody = jsonBody.toString();
URL url = new URL("https://fcm.googleapis.com/fcm/send");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Authorization", "key=" + serverKey);
conn.setRequestProperty("Content-Type", "application/json");
conn.setDoOutput(true);
OutputStream outputStream = conn.getOutputStream();
outputStream.write(requestBody.getBytes());
outputStream.flush();
outputStream.close();
int responseCode = conn.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
    // 消息发送成功
}
// 接收和处理消息的服务类
public class MyFirebaseMessagingService extends FirebaseMessagingService {
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
        // 处理接收到的消息，并展示通知
    }
}