delphi IdTCPClient1 自动接收消息

procedure TForm1.Timer1Timer(Sender: TObject);
var
 Buf: TIdBytes=nil;
 n: Integer;
 S: String;
begin
 if IdTCPClient1.IOHandler.InputBufferIsEmpty then begin
   if not IdTCPClient1.IOHandler.CheckForDataOnSource(0) then begin
     IdTCPClient1.IOHandler.CheckForDisconnect;
     Exit;
   end;
 end;
 Timer1.Enabled := false;
 IdTCPClient1.IOHandler.ReadBytes(Buf, 5, False);
 S := 'HEX: ';
 for n := 0 to Length(Buf)-1 do
   S := S + IntToHex(Buf[n], 2) + ' ';
 Timer1.Enabled := true;
end;