AudioSession.GetString C# (CSharp) Méthode

        private static string GetString(GetStringFn fn)
        {
            fn(out var ptr);
            if (ptr == IntPtr.Zero)
                return null;
            try
            {
                var s = Marshal.PtrToStringUni(ptr);
                if (!string.IsNullOrWhiteSpace(s) && s.StartsWith("@"))
                {
                    var sb = new StringBuilder(256);
                    if (SHLoadIndirectString(s, sb, sb.Capacity, IntPtr.Zero) == 0)
                    {
                        s = sb.ToString();
                    }
                }
                return s;
            }
            finally
            {
                Marshal.FreeCoTaskMem(ptr);
            }
        }
        private Icon GetIcon()