func (cli *Client) head(ctx context.Context, path string, query url.Values, headers map[string][]string) (serverResponse, error) {
	return cli.sendRequest(ctx, "HEAD", path, query, nil, headers)
}
head sends an http request to the docker API using the method HEAD.
package client
import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net"
	"net/http"
	"net/url"
	"os"
	"strings"
	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/versions"
	"github.com/pkg/errors"
	"golang.org/x/net/context"
	"golang.org/x/net/context/ctxhttp"
)
type serverResponse struct {
	body       io.ReadCloser
	header     http.Header
	statusCode int
}