✅ How read text output from already started process?

var proc = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = "stockfish-windows-2022-x86-64-avx2.exe",
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                }
            };
            while(true) //i know thats bad
            {
                StreamReader reader = proc.StandardOutput;
                string line = reader.ReadLine();
                Debug.WriteLine(line);
            }

System.InvalidOperationException: "StandardOut has not been redirected or the process hasn't started yet."