UnityECS/Assets/Scripts/Server/ServerConnectionJob.cs

    using Unity.Burst;
    using Unity.Collections;
    using Unity.Jobs;
    using Unity.Networking.Transport;
    using UnityEngine;

    [BurstCompile]
    public struct ServerConnectionJob : IJob
    {
        public NetworkDriver driver;
        public NativeList<NetworkConnection> connectionList;
        public NativeList<int> disconnectIndexList;
        
        public void Execute()
        {
            // disconnect
            disconnectIndexList.Sort();
            for (int i = disconnectIndexList.Length - 1; i >= 0; --i)
            {
                var index = disconnectIndexList[i];
                connectionList.RemoveAtSwapBack(index);
            }
            disconnectIndexList.Clear();

            // connect
            NetworkConnection c;
            while ((c = driver.Accept()) != default)
            {
                connectionList.Add(c);
                Debug.Log("Accepted a connection");
            }
        }
    }