Native VisxAdManager in Flutter

I would implement visxAds (from instruction https://support.yoc.com/android-sdk/integration/configuring-the-ad-unit/) in Flutter app. I don't know if this is possible.

In that instruction (configuring the ad unit) is native android (kotlin) code but not exist instruction for Flutter (dart) code. I need help.

In that instruction is code:

<RelativeLayout
android:id="@+id/inlineContainer"
android:layout_width="0dip"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />

but in Flutter I don't do write like this.

from Native VisxAdManager in Flutter