code: func (em *Emitter) Subscribe(ctx context.Context, subscriber string, queryable query.Queryable, bufferSize int) (<-chan interface{}, error) {
  	qry, err := queryable.Query()
  	if err != nil {
  		return nil, err
  	}
  	return em.pubsubServer.Subscribe(ctx, subscriber, qry, bufferSize)
  }
docs: // Subscribe tells the emitter to listen for messages on the given query