func New(url string) (*PartialZip, error) {
	pz := &PartialZip{URL: url}
	err := pz.init()
	if err != nil {
		return nil, errors.Wrap(err, "failed to read http response body")
	}
	return pz, nil
}
New returns a newly created partialzip object.
package partialzip
import (
	"bufio"
	"bytes"
	"compress/flate"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"strings"
	"github.com/pkg/errors"
)
type PartialZip struct {
	URL   string
	Size  int64
	Files []*File
}