Function write_non_window_touch_messages_system 

pub fn write_non_window_touch_messages_system(
    focused_non_window_egui_context: Option<Res<'_, FocusedNonWindowEguiContext>>,
    touch_input_reader: MessageReader<'_, '_, TouchInput>,
    egui_input_message_writer: MessageWriter<'_, EguiInputEvent>,
    modifier_keys_state: Res<'_, ModifierKeysState>,
    egui_contexts: Query<'_, '_, (&EguiContextSettings, &EguiContextPointerPosition, &mut EguiContextPointerTouchId, &EguiOutput), With<EguiContext>>,
)

Reads TouchInput messages and wraps them into EguiInputEvent for a HoveredNonWindowEguiContext context (if one exists).