code: func NewSearchSource() *SearchSource {
  	return &SearchSource{
  		from:         -1,
  		size:         -1,
  		aggregations: make(map[string]Aggregation),
  		indexBoosts:  make(map[string]float64),
  		innerHits:    make(map[string]*InnerHit),
  	}
  }
docs: // NewSearchSource initializes a new SearchSource.