Screen Reader is slow to start reading a loaded QML component on Android

When a QML component is loading on Android while the TalkBack screen reader is running, the Qt framework fires too many TYPE_WINDOW_CONTENT_CHANGED accessibility events. This makes TalkBack slow to starting reading a QML component, because the flood of events need to be processed before TalkBack can start reading.

A lot of QQuickItem::geometryChange calls happen during the component loading. This leads to QQuickItem::geometryChange calling QAccessible::updateAccessibility(QAccessible::LocationChanged), which triggers QtAccessibilityDelegate.notifyLocationChange. Eventually, this leads to as many sendEventForVirtualViewId(TYPE_WINDOW_CONTENT_CHANGED) calls on Android.

This delay in screen reading can be 10 seconds or more for a medium or large QML component.

A possible fix could be for Qt to collapse these TYPE_WINDOW_CONTENT_CHANGED events into one when a QML component is loading.

See a similar problem in the Flutter framework here: https://github.com/flutter/flutter/issues/14534

Please consider fixing this issue because it has a big effect on Accessibility on Android.