pop backstack to a known fragment

BackStackActivity.kt

 private fun popToKnownFragment(fragment : Fragment) {
        if (!lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED))
            return

        val isPopped = supportFragmentManager.popBackStackImmediate(fragment::class.simpleName, 0)
        if (!isPopped) {
            // code inside here is only executed because fragment transaction didnt happen because 
            // the fragment above does not exist in the backstack or it was added with a different tag. 
            // Since this fragment must be shown, add a new instance of it
            supportFragmentManager.beginTransaction()
                    .replace(R.id.app_container, fragment, fragment::class.simpleName)
                    .addToBackStack(fragment::class.simpleName)
                    .commit()
        }

    }