func (f Get) WithHeader(h map[string]string) func(*GetRequest) {
	return func(r *GetRequest) {
		if r.Header == nil {
			r.Header = make(http.Header)
		}
		for k, v := range h {
			r.Header.Add(k, v)
		}
	}
}
WithHeader adds the headers to the HTTP request.
package opensearchapi
import (
	"context"
	"net/http"
	"strconv"
	"strings"
)
func newGetFunc(t Transport) Get {
	return func(index string, id string, o ...func(*GetRequest)) (*Response, error) {
		var r = GetRequest{Index: index, DocumentID: id}
		for _, f := range o {
			f(&r)
		}
		return r.Do(r.ctx, t)
	}
}
type Get func(index string, id string, o ...func(*GetRequest)) (*Response, error)
type GetRequest struct {
	Index        string
	DocumentType string
	DocumentID   string
	Preference     string
	Realtime       *bool
	Refresh        *bool
	Routing        string
	Source         []string
	SourceExcludes []string
	SourceIncludes []string
	StoredFields   []string
	Version        *int
	VersionType    string
	Pretty     bool
	Human      bool
	ErrorTrace bool
	FilterPath []string
	Header http.Header
	ctx context.Context
}
func (r GetRequest) Do(ctx context.Context, transport Transport) (*Response, error) {
	var (
		method string
		path   strings.Builder
		params map[string]string
	)
	method = "GET"
	if r.DocumentType == "" {
		r.DocumentType = "_doc"
	}
	path.Grow(1 + len(r.Index) + 1 + len(r.DocumentType) + 1 + len(r.DocumentID))
	path.WriteString("/")
	path.WriteString(r.Index)
	if r.DocumentType != "" {
		path.WriteString("/")
		path.WriteString(r.DocumentType)
	}
	path.WriteString("/")
	path.WriteString(r.DocumentID)
	params = make(map[string]string)
	if r.Preference != "" {
		params["preference"] = r.Preference
	}
	if r.Realtime != nil {
		params["realtime"] = strconv.FormatBool(*r.Realtime)
	}
	if r.Refresh != nil {
		params["refresh"] = strconv.FormatBool(*r.Refresh)
	}
	if r.Routing != "" {
		params["routing"] = r.Routing
	}
	if len(r.Source) > 0 {
		params["_source"] = strings.Join(r.Source, ",")
	}
	if len(r.SourceExcludes) > 0 {
		params["_source_excludes"] = strings.Join(r.SourceExcludes, ",")
	}
	if len(r.SourceIncludes) > 0 {
		params["_source_includes"] = strings.Join(r.SourceIncludes, ",")
	}
	if len(r.StoredFields) > 0 {
		params["stored_fields"] = strings.Join(r.StoredFields, ",")
	}
	if r.Version != nil {
		params["version"] = strconv.FormatInt(int64(*r.Version), 10)
	}
	if r.VersionType != "" {
		params["version_type"] = r.VersionType
	}
	if r.Pretty {
		params["pretty"] = "true"
	}
	if r.Human {
		params["human"] = "true"
	}
	if r.ErrorTrace {
		params["error_trace"] = "true"
	}
	if len(r.FilterPath) > 0 {
		params["filter_path"] = strings.Join(r.FilterPath, ",")
	}
	req, err := newRequest(method, path.String(), nil)
	if err != nil {
		return nil, err
	}
	if len(params) > 0 {
		q := req.URL.Query()
		for k, v := range params {
			q.Set(k, v)
		}
		req.URL.RawQuery = q.Encode()
	}
	if len(r.Header) > 0 {
		if len(req.Header) == 0 {
			req.Header = r.Header
		} else {
			for k, vv := range r.Header {
				for _, v := range vv {
					req.Header.Add(k, v)
				}
			}
		}
	}
	if ctx != nil {
		req = req.WithContext(ctx)
	}
	res, err := transport.Perform(req)
	if err != nil {
		return nil, err
	}
	response := Response{
		StatusCode: res.StatusCode,
		Body:       res.Body,
		Header:     res.Header,
	}
	return &response, nil
}
func (f Get) WithContext(v context.Context) func(*GetRequest) {
	return func(r *GetRequest) {
		r.ctx = v
	}
}
func (f Get) WithDocumentType(v string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.DocumentType = v
	}
}
func (f Get) WithPreference(v string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Preference = v
	}
}
func (f Get) WithRealtime(v bool) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Realtime = &v
	}
}
func (f Get) WithRefresh(v bool) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Refresh = &v
	}
}
func (f Get) WithRouting(v string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Routing = v
	}
}
func (f Get) WithSource(v ...string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Source = v
	}
}
func (f Get) WithSourceExcludes(v ...string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.SourceExcludes = v
	}
}
func (f Get) WithSourceIncludes(v ...string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.SourceIncludes = v
	}
}
func (f Get) WithStoredFields(v ...string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.StoredFields = v
	}
}
func (f Get) WithVersion(v int) func(*GetRequest) {
	return func(r *GetRequest) {
		r.Version = &v
	}
}
func (f Get) WithVersionType(v string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.VersionType = v
	}
}
func (f Get) WithPretty() func(*GetRequest) {
	return func(r *GetRequest) {
		r.Pretty = true
	}
}
func (f Get) WithHuman() func(*GetRequest) {
	return func(r *GetRequest) {
		r.Human = true
	}
}
func (f Get) WithErrorTrace() func(*GetRequest) {
	return func(r *GetRequest) {
		r.ErrorTrace = true
	}
}
func (f Get) WithFilterPath(v ...string) func(*GetRequest) {
	return func(r *GetRequest) {
		r.FilterPath = v
	}
}