anchor.diff:          size += await fse.length();
         }
       }
  +    _logger.info('($_id) Current size of pub cache dir: $size');
       _isAboveSizeLimit = size > _maxSize;
     }
   }
  
positive.code: 
    bool get _isAvailable => _started < _maxCount && !_isAboveSizeLimit;
  
    void _aquire() {
      _started++;
      _active++;
    }
  
    Future<void> release() async {
      await _checkSizeLimit();
      _active--;
      if (_active == 0) {
        // Delete directory if the instance is no longer active or it reached the
        // maximum threshold.
        if (_started >= _maxCount || _current != this) {
          await _pubCacheDir.delete(recursive: true);
        }
      }
  
negative.code:     );
      _current = ToolEnvRef(cacheDir, toolEnv);
      result = _current;
      result._acquire();
      _ongoing.complete();
      _ongoing = null;
      break;
  