code: protected function determineStreamName(string $aggregateId): StreamName
      {
          if ($this->oneStreamPerAggregate) {
              if (null === $this->streamName) {
                  $prefix = $this->aggregateType->toString();
              } else {
                  $prefix = $this->streamName->toString();
              }
  
              return new StreamName($prefix . '-' . $aggregateId);
          }
  
          if (null === $this->streamName) {
              return new StreamName('event_stream');
          }
  
          return $this->streamName;
      }
docs: Default stream name generation.
  Override this method in an extending repository to provide a custom name