Discord.Net example code not working

public class Program
{
    private static DiscordSocketClient _client;
    
    public async Task Main()
    {
        _client = new DiscordSocketClient();
        _client.Log += Log;
        
        await _client.LoginAsync(TokenType.Bot, 
            Environment.GetEnvironmentVariable("TOKEN"));
        await _client.StartAsync();
        
        // Block this task until the program is closed.
        await Task.Delay(-1);
    }
    
    private Task Log(LogMessage msg)
    {
        Console.WriteLine(msg.ToString());
        return Task.CompletedTask;
    }
}

    dotnet run
/home/defnotadolph/Documents/Projects/Fish-With-A-Harpoon/Program.cs(18,22): error CS0246: The type or namespace name 'LogMessage' could not be found (are you missing a using directive or an assembly reference?)
/home/defnotadolph/Documents/Projects/Fish-With-A-Harpoon/Program.cs(3,20): error CS0246: The type or namespace name 'DiscordSocketClient' could not be found (are you missing a using directive or an assembly reference?)

The build failed. Fix the build errors and run again.