procedure TForm1.Button3Click(Sender: TObject);
var
  fs: tfilestream;
  ms:tmemorystream;
  ilast:int64;
  inext:integer;
  stream: tidstreamvcl;
begin
fs:= tfilestream.Create('c:\katze1.jpg',fmopenread);
ms:= tmemorystream.Create;
ilast:=0;
while (ilast < fs.Size) do begin
  inext:= fs.Size-ilast;
  if inext > 10000 then
    inext:=10000;
  fs.Position:=ilast;
  ms.CopyFrom(fs,inext);
  try
  stream:= tidstreamvcl.Create(ms);
  memo1.lines.add('infos '+inttostr(ilast)+' '+inttostr(stream.Size)+' '+inttostr(ms.size));
  finally
  client.Socket.WriteBufferOpen;
  //sleep(50);
  client.Socket.Write(stream,stream.size,true);
  //sleep(50);
  client.Socket.WriteBufferClose;
  //client.Socket.WriteBuffercancel;
  stream.free;
  ilast:=ilast+inext;
  end;
end;
ms.Free;
fs.free;
end;