findTopFirstVisibleItemPosition method
Implementation
int findTopFirstVisibleItemPosition() {
var r = itemPositionsListener.itemPositions.value
.where((ItemPosition position) => position.itemTrailingEdge < 1)
.reduce((ItemPosition min, ItemPosition position) =>
position.itemTrailingEdge > min.itemTrailingEdge ? position : min)
.index;
return r; //< chatList.length ? r + 1 : r;
}