ROSInitializer.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using ROSBridgeLib;

public class ROSInitializer : MonoBehaviour
{
    public ROSBridgeWebSocketConnection ros = null;
    
    void Start() {
        // rosbridge_server node has to be launched before: 
        // roslaunch rosbridge_server rosbridge_websocket.launch
        // Where the rosbridge instance is running, could be localhost, or some external IP (9090 default port)
        ros = new ROSBridgeWebSocketConnection ("ws://localhost", 9090); 

        // Add subscribers and publishers (if any)
        ros.AddSubscriber(typeof(PointCloudSubscriber));
        ros.AddSubscriber(typeof(TFSubscriber));
        
        // Fire up the subscriber(s) and publisher(s)
        ros.Connect ();
    }
  
    // Extremely important to disconnect from ROS. Otherwise packets continue to flow
    void OnApplicationQuit() {
        if(ros!=null) {
            ros.Disconnect ();
        }
    }
    // Update is called once per frame in Unity
    void Update () {
        ros.Render ();
    }
}