anchor.diff:      assert(start < end);
   
       int current = start;
  -    if(_lengthRequired == null && current < end) {
  +    if(_lengthRequired == null) {
         current = _lineConsumer.consume(data, current, end);
         if(_lineConsumer.done) {
           final specifiedLength =
  
positive.code:       }
      } else {
        if(_activeConsumer == null) {
          _activeConsumer = _makeRedisConsumer(current++);
        }
        if(current < end) {
          current = _activeConsumer.consume(data, current, end);
  
negative.code:       current = takeTo;
      }
  
      if(current < end && !done) {
        current = consume(data, current, end);
      }
  
  