anchor.diff:  
     final int limit;
   
  +  bool get limitted => limit > 0;
  +
     /**
      * Create a stream buffer with optional, soft [limit] to the amount of data
      * the buffer will hold before pausing the underlying straem. A limit of 0
  
positive.code:         _chunks.removeAt(0);
        }
      }
      if (_sub.isPaused && limit > 0 && _counter < limit) {
        _sub.resume();
      }
      return ret;
  
negative.code:   Future<List<T>> read(int size) {
      // If we have enough data to consume and there are no other readers, then
      // we can return immediately.
      if (limitted && size > limit) {
        throw new ArgumentError("Cannot read $size with limit $limit");
      }
  
  