You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: api.cluster.state.go
    path of file: ./repos/corteza/extra/server-discovery/vendor/github.com/elastic/go-elasticsearch/v7/esapi
    
    the code of the file until where you have to start completion: // Licensed to Elasticsearch B.V under one or more agreements.
// Elasticsearch B.V. licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information.
//
// Code generated from specification version 7.12.0: DO NOT EDIT

package esapi

import (
	"context"
	"net/http"
	"strconv"
	"strings"
	"time"
)

func newClusterStateFunc(t Transport) ClusterState {
	return func(o ...func(*ClusterStateRequest)) (*Response, error) {
		var r = ClusterStateRequest{}
		for _, f := range o {
			f(&r)
		}
		return r.Do(r.ctx, t)
	}
}

// ----- API Definition -------------------------------------------------------

// ClusterState returns a comprehensive information about the state of the cluster.
//
// See full documentation at https://www.elastic.co/guide/en/elasticsearch/reference/master/cluster-state.html.
//
type ClusterState func(o ...func(*ClusterStateRequest)) (*Response, error)

// ClusterStateRequest configures the Cluster State API request.
//
type ClusterStateRequest struct {
	Index []string

	Metric []string

	AllowNoIndices         *bool
	ExpandWildcards        string
	FlatSettings           *bool
	IgnoreUnavailable      *bool
	Local                  *bool
	MasterTimeout          time.Duration
	WaitForMetadataVersion *int
	WaitForTimeout         time.Duration

	Pretty     bool
	Human      bool
	ErrorTrace bool
	FilterPath []string

	Header http.Header

	ctx context.Context
}

// Do executes the request and returns response or error.
//
func (r ClusterStateRequest) Do(ctx context.Context, transport Transport) (*Response, error) {
	var (
		method string
		path   strings.Builder
		params map[string]string
	)

	method = "GET"

	path.Grow(1 + len("_cluster") + 1 + len("state") + 1 + len(strings.Join(r.Metric, ",")) + 1 + len(strings.Join(r.Index, ",")))
	path.WriteString("/")
	path.WriteString("_cluster")
	path.WriteString("/")
	path.WriteString("state")
	if len(r.Metric) > 0 {
		path.WriteString("/")
		path.WriteString(strings.Join(r.Metric, ","))
	}
	if len(r.Index) > 0 {
		path.WriteString("/")
		path.WriteString(strings.Join(r.Index, ","))
	}

	params = make(map[string]string)

	if r.AllowNoIndices != nil {
		params["allow_no_indices"] = strconv.FormatBool(*r.AllowNoIndices)
	}

	if r.ExpandWildcards != "" {
		para
    
func (r ClusterStateRequest) Do(ctx context.Context, transport Transport) (*Response, error) {
	var (
		method string
		path   strings.Builder
		params map[string]string
	)

	method = "GET"

	path.Grow(1 + len("_cluster") + 1 + len("state") + 1 + len(strings.Join(r.Metric, ",")) + 1 + len(strings.Join(r.Index, ",")))
	path.WriteString("/")
	path.WriteString("_cluster")
	path.WriteString("/")
	path.WriteString("state")
	if len(r.Metric) > 0 {
		path.WriteString("/")
		path.WriteString(strings.Join(r.Metric, ","))
	}
	if len(r.Index) > 0 {
		path.WriteString("/")
		path.WriteString(strings.Join(r.Index, ","))
	}

	params = make(map[string]string)

	if r.AllowNoIndices != nil {
		params["allow_no_indices"] = strconv.FormatBool(*r.AllowNoIndices)
	}

	if r.ExpandWildcards != "" {
		params["expand_wildcards"] = r.ExpandWildcards
	}

	if r.FlatSettings != nil {
		params["flat_settings"] = strconv.FormatBool(*r.FlatSettings)
	}

	if r.IgnoreUnavailable != nil {
		params["ignore_unavailable"] = strconv.FormatBool(*r.IgnoreUnavailable)
	}

	if r.Local != nil {
		params["local"] = strconv.FormatBool(*r.Local)
	}

	if r.MasterTimeout != 0 {
		params["master_timeout"] = formatDuration(r.MasterTimeout)
	}

	if r.WaitForMetadataVersion != nil {
		params["wait_for_metadata_version"] = strconv.FormatInt(int64(*r.WaitForMetadataVersion), 10)
	}

	if r.WaitForTimeout != 0 {
		params["wait_for_timeout"] = formatDuration(r.WaitForTimeout)
	}

	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
}