func (s *DeleteByQueryService) Header(name string, value string) *DeleteByQueryService {
	if s.headers == nil {
		s.headers = http.Header{}
	}
	s.headers.Add(name, value)
	return s
}
Header adds a header to the request.
package elastic
import (
	"context"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"github.com/olivere/elastic/v7/uritemplates"
)
type DeleteByQueryService struct {
	client *Client
	pretty     *bool        
	human      *bool        
	errorTrace *bool        
	filterPath []string     
	headers    http.Header  
	index                  []string
	typ                    []string
	query                  Query
	body                   interface{}
	xSource                []string
	xSourceExclude         []string
	xSourceInclude         []string
	analyzer               string
	analyzeWildcard        *bool
	allowNoIndices         *bool
	conflicts              string
	defaultOperator        string
	df                     string
	docvalueFields         []string
	expandWildcards        string
	explain                *bool
	from                   *int
	ignoreUnavailable      *bool
	lenient                *bool
	lowercaseExpandedTerms *bool
	preference             string
	q                      string
	refresh                string
	requestCache           *bool
	requestsPerSecond      *int
	routing                []string
	scroll                 string
	scrollSize             *int
	searchTimeout          string
	searchType             string
	size                   *int
	slices                 interface{}
	sort                   []string
	stats                  []string
	storedFields           []string
	suggestField           string
	suggestMode            string
	suggestSize            *int
	suggestText            string
	terminateAfter         *int
	timeout                string
	trackScores            *bool
	version                *bool
	waitForActiveShards    string
	waitForCompletion      *bool
}
func NewDeleteByQueryService(client *Client) *DeleteByQueryService {
	builder := &DeleteByQueryService{
		client: client,
	}
	return builder
}
func (s *DeleteByQueryService) Pretty(pretty bool) *DeleteByQueryService {
	s.pretty = &pretty
	return s
}
func (s *DeleteByQueryService) Human(human bool) *DeleteByQueryService {
	s.human = &human
	return s
}
func (s *DeleteByQueryService) ErrorTrace(errorTrace bool) *DeleteByQueryService {
	s.errorTrace = &errorTrace
	return s
}
func (s *DeleteByQueryService) FilterPath(filterPath ...string) *DeleteByQueryService {
	s.filterPath = filterPath
	return s
}