A logger for Discord RPC C# for use within the Unity3D engine.

DebugLogger.cs

class DebugLogger : DiscordRPC.Logging.ILogger
	{
		public LogLevel Level { get; set; }
				
		public void Info(string message, params object[] args)
		{
			if (Level != LogLevel.Info) return;
			Debug.Log("[DRPC] " + string.Format(message, args));
		}

		public void Warning(string message, params object[] args)
		{
			if (Level != LogLevel.Info && Level != LogLevel.Warning) return;
			Debug.LogWarning("[DRPC] " + string.Format(message, args));
		}

		public void Error(string message, params object[] args)
		{
			if (Level != LogLevel.Info && Level != LogLevel.Warning && Level != LogLevel.Error) return;
			Debug.LogError("[DRPC] " + string.Format(message, args));
		}

	}

I think you forgot those two lines :

using DiscordRPC.Logging;
using UnityEngine;

And the class need to be public to be used
So we have this :

using DiscordRPC.Logging;
using UnityEngine;

public class DebugLogger : DiscordRPC.Logging.ILogger
{
    public LogLevel Level { get; set; }

    public void Info(string message, params object[] args)
    {
        if (Level != LogLevel.Info) return;
        Debug.Log("[DRPC] " + string.Format(message, args));
    }

    public void Warning(string message, params object[] args)
    {
        if (Level != LogLevel.Info && Level != LogLevel.Warning) return;
        Debug.LogWarning("[DRPC] " + string.Format(message, args));
    }

    public void Error(string message, params object[] args)
    {
        if (Level != LogLevel.Info && Level != LogLevel.Warning && Level != LogLevel.Error) return;
        Debug.LogError("[DRPC] " + string.Format(message, args));
    }
}