how to change the white circle to a icon?

この issue には説明がありません。

The issue asks about changing a white circle to an icon in a Flutter pull-to-refresh widget. Look at the library's main widget file (likely lib/liquid_pull_to_refresh.dart) to see how the refresh indicator is built. Check for properties controlling the indicator's appearance and see if there is an existing way to customize it with an icon. Review example code in the repository to understand the current usage.

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