var
 lOverlapped: OVERLAPPED;
 lLastError, BytesTrans: Cardinal;
 lEvent: TEvent;
 Task: ITask;
 TmpBuf: TMyByteArray;
 CanWrite: Boolean;
begin

 if UsbHandle = INVALID_HANDLE_VALUE then
exit(-1);


 SetLength(TmpBuf, Count);
 ZeroMemory(TmpBuf, Length(TmpBuf));
 lEvent := TEvent.Create(nil, FALSE, FALSE, '');
 FillChar(lOverlapped, SizeOf(lOverlapped), 0);
 lOverlapped.hEvent := lEvent.Handle;
 CanWrite := ReadFile(UsbHandle, TmpBuf[0], Count, BytesTrans, @lOverlapped);

 try
   if not CanWrite then
   begin

     lLastError := GetLastError;

     if (lLastError <> ERROR_IO_PENDING) then
       exit;
     Task := TTASK.Create(
       procedure
       begin

         case lEvent.WaitFor(12000) of
           wrSignaled:
             if not GetOverlappedResult(UsbHandle, lOverlapped, BytesTrans,
               FALSE) then
               exit;

           wrError:
             begin
               lLastError := lEvent.LastError;

               if CancelIo(UsbHandle) then
                 lEvent.WaitFor(12000);
               exit;
             end;
         end;

         CanWrite := True;

       end);
     Task.Start();

     while Task.STATUS <> TTASKSTATUS.COMPLETED do
     begin
       IF(Task.STATUS = TTASKSTATUS.EXCEPTION) THEN
       exit(-1);
       Application.ProcessMessages;

     end;

     if not CanWrite then
     exit(-1);

   end;

   Result := BytesTrans;
   SetLength(TmpBuf, BytesTrans);
   MoveMemory(@Buffer, @TmpBuf[0], Length(TmpBuf));
   Application.ProcessMessages;
 finally
   FreeAndNil(lEvent);
 end;