How can I get PID(process id) of window/tab I'm currently active in Flutter windows application?

import 'dart:io'
...
print(pid);

This code print the pid of my Flutter application. But I want to get the other apps' pid when I switch on that app. Suppose, I am now on skype app. So this print(pid) will print pid of skype. When I switch on notepad it will print notepads pid. Is there any way to do that? Thanks in advance.

I've searched way to access psapi.dll using dart:ffi. But got nothing.

Finally I was able to find the solution.

import 'dart:ffi' as ffi;
import 'package:ffi/ffi.dart';
import 'package:win32/win32.dart';


void main() {
    ffi.Pointer<ffi.Uint32> pidPointer = calloc();
    int hwnd = GetForegroundWindow();

    GetWindowThreadProcessId(hwnd, pidPointer);

    int pid = pidPointer.value;

    print('Process ID of the active window: $pid');
    free(pidPointer);
}