func (s *IndicesFlushService) Force(force bool) *IndicesFlushService {
	s.force = &force
	return s
}
Force indicates whether a flush should be forced even if it is not
necessarily needed ie. if no changes will be committed to the index.
This is useful if transaction log IDs should be incremented even if
no uncommitted changes are present. (This setting can be considered as internal).
package elastic
import (
	"fmt"
	"net/url"
	"strings"
	"gopkg.in/olivere/elastic.v3/uritemplates"
)
type IndicesFlushService struct {
	client            *Client
	pretty            bool
	index             []string
	force             *bool
	waitIfOngoing     *bool
	ignoreUnavailable *bool
	allowNoIndices    *bool
	expandWildcards   string
}
func NewIndicesFlushService(client *Client) *IndicesFlushService {
	return &IndicesFlushService{
		client: client,
		index:  make([]string, 0),
	}
}
func (s *IndicesFlushService) Index(indices ...string) *IndicesFlushService {
	s.index = append(s.index, indices...)
	return s
}