onRefresh property
Border width of progressing circle in Progressing Indicator
default to 2.0 Whether to show child opacity transition or not.
default to true A function that's called when the user has dragged the progress indicator far enough to demonstrate that they want the app to refresh. The returned Future must complete when the refresh operation is finished.
Implementation
/// Whether to show child opacity transition or not.
///
/// default to true
/// A function that's called when the user has dragged the progress indicator
/// far enough to demonstrate that they want the app to refresh. The returned
/// [Future] must complete when the refresh operation is finished.
final RefreshCallback onRefresh;