anchor.diff:  import 'package:angel_multiserver/angel_multiserver.dart';
   
   final Uri cluster = Platform.script.resolve('cluster.dart');
  -final errorPage = GZIP.encode(UTF8.encode('''
  +final error502 = GZIP.encode(UTF8.encode('''
  +        <!DOCTYPE html>
  +        <html>
  +          <head>
  +            <title>502 Bad Gateway</title>
  +          </head>
  +          <body>
  +            <h1>502 Bad Gateway</h1>
  +          </body>
  +        </html>
  +        '''));
  +final error503 = GZIP.encode(UTF8.encode('''
           <!DOCTYPE html>
           <html>
             <head>
  
positive.code:   var server = await loadBalancer.startServer();
    print(
        'Load balancer listening at http://${server.address.address}:${server.port}');
  }
negative.code:       // Auto-spawn a new instance on crash
        loadBalancer.spawnIsolates(cluster);
      })
      ..onErrored.listen((socket) async {
         try {
           socket
             ..writeln('HTTP/1.1 502 Bad Gateway')
             ..writeln(HttpDate.format(new DateTime.now()))
             ..writeln('Content-Encoding: gzip')
             ..writeln()
             ..add(error502)
             ..writeln();
        await socket.close();
         } catch(_) {}
      })
      ..onUnavailable.listen((socket) async {
        socket
          ..writeln('HTTP/1.1 503 Service Unavailable')
          ..writeln(HttpDate.format(new DateTime.now()))
          ..writeln('Content-Encoding: gzip')
          ..writeln()
          ..add(error503)
          ..writeln();
        await socket.close();
      });
  