anchor.diff:  // connection port.
   
   import "dart:io";
  -import "dart:json";
  +import "dart:json" as json;
   import "dart:utf";
  +import "dart:async";
   
   
   Map<int, Completer> outstandingCommands;
  
positive.code: }
  
  
  void processVmMessage(String json) {
    var msg = parseJson(json);
    if (msg == null) {
      return;
    }
  
negative.code:   int id = cmd["id"];
    outstandingCommands[id] = completer;
    if (verbose) {
      print("sending: '${json.stringify(cmd)}'");
    }
    vmStream.writeString(json.stringify(cmd));
    return completer.future;
  }
  
  