LazyBlock({Key key, @required LazyBlockDelegate delegate, double initialScrollOffset, Axis scrollDirection: Axis.vertical, ScrollListener onScrollStart, ScrollListener onScroll, ScrollListener onScrollEnd, SnapOffsetCallback snapOffsetCallback, Key scrollableKey, EdgeInsets padding })

Creates an infinite scrolling list of variable height children.

The delegate argument must not be null.

Source 

LazyBlock({
  Key key,
  @required this.delegate,
  this.initialScrollOffset,
  this.scrollDirection: Axis.vertical,
  this.onScrollStart,
  this.onScroll,
  this.onScrollEnd,
  this.snapOffsetCallback,
  this.scrollableKey,
  this.padding
}) : super(key: key) {
  assert(delegate != null);
}