anchor.diff:  import 'dart:io';
   
   import 'package:crypto/crypto.dart' as crypto;
  +import 'dart:math';
   
   /// Return a string that is at most 300 char long.
   String trim300(String exMsg) {
  
positive.code:   /// if a non sequential block is found.
    bool allowNonSequentialMsgs;
  
    /// `true` if [allowNonSequentialMsgs] is `true`
    /// and a non sequential block is found.
    bool hasNonSequentialMsgs = false;
  
    _LogItemSink(this._sink, this.allowNonSequentialMsgs);
  
  
negative.code:     if (sink is! StringConversionSink) {
        sink = new StringConversionSink.from(sink);
      }
      _logSink = new _LogItemSink(sink, allowNonSequentialMsgs);
      return _logSink;
    }
  }
  
  