delphi idhttp续传问题

Question

我用idhttp实现文件的某块下载，为什么每次都是把整个文件都下下来了,我设的下载部分远小于源文件大小啊？我的程序如下：

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, idhttp, idantifreeze, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
my:tidhttp;
an:tidantifreeze;
size:integer;
url:string;
s:tmemorystream;
begin
my:=tidhttp.Create(nil);
an:=tidantifreeze.Create(nil);
an.OnlyWhenIdle:=false;
s:=tmemorystream.Create;
url:='http://xxx.xxx.com/0001.JPG';
//my.Head(url);
//size:=my.Response.ContentLength;
//edit1.Text:=inttostr(size);
my.Request.ContentRangeStart:=1;
my.Request.ContentRangeEnd:=1700;
my.Get(url,s);
s.SaveToFile('d:\4.jpg');
s.Clear;
my.Destroy;
end;

end.

Answer 1

占楼关注。应该是支持续传的，具体的我也不会。
有时间看一下文档。