set_indicator_icon

Sets the indicator icon of this.

A common use case is an audio or camera indicator in a web browser.

[class@TabBar] will show it at the beginning of the tab, alongside icon representing [property@TabPage:icon] or loading spinner.

If the page is pinned, the indicator will be shown instead of icon or spinner.

[class@TabOverview] will show it at the at the top part of the thumbnail.

[property@TabPage:indicator-tooltip] can be used to set the tooltip on the indicator icon.

If [property@TabPage:indicator-activatable] is set to `TRUE`, the indicator icon can act as a button.

Parameters:

this	a tab page
indicator_icon	the indicator icon of this