Solved Error CS0234: The type or namespace name 'Tasks' does not exosit in the namespace 'System.Threading'

Getting my feet wet with Rust plugin development, and getting this error. Not sure what reference I'm missing. I have
Assembly-CSharp
Facepunch.Network
Facepunch.System
Facepunch.UnityEngine
Oxide.Core
Oxide.Core.CSharp
Oxide.Game.Rust
UnityEngine
UnityEngine.UI

Error while compiling: RustyRockets.cs(6,24): error CS0234: The type or namespace name `Tasks' does not exist in the namespace `System.Threading'. Are you missing an assembly reference?

Here is a bit of my code

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Reflection;
using Oxide.Core;
using Oxide.Core.CSharp;
using Oxide.Core.Plugins;
using Oxide.Game.Rust.Libraries;
using UnityEngine;namespace Oxide.Plugins
{
    [Info("RustyRockets", "Tanner", 0.1)]
    [Description("Gives Rockets and C4 to everyone on the server at the time you want!")]    class RustyRockets : RustPlugin
    {
        void Loaded()
        {
            Puts("[RustyRockets] Loaded.");
        }        void UnLoaded()
        {
            Puts("[RustyRockets] Unloaded.");
        }        [ChatCommand("RustyRockets")]
        void pofpl(BasePlayer player, string command, string[] args)
        {
            player.inventory.GiveItem(ItemManager.CreateByItemID(1578894260, 100)); //Rockets
            player.inventory.GiveItem(ItemManager.CreateByItemID(498591726, 100)); //C4
        }
    }}

Thanks.

 

Right, I meant to change that to Unload, also didn't know that they automatically did it, thanks. Removing the using statements fixed it.