Improve the SliverChildBuilderDelegate docs for folk to troubleshoot. (#103183)

Author: xu-baolin

packages/flutter/lib/src/widgets/sliver.dart

@@ -375,6 +375,11 @@ class SliverChildBuilderDelegate extends SliverChildDelegate {
   /// Should return null if asked to build a widget with a greater index than
   /// exists.
   ///
+  /// May result in an infinite loop or run out of memory if [childCount] is null
+  /// and the [builder] always provides a zero-size widget (such as `Container()`
+  /// or `SizedBox.shrink()`). If possible, provide children with non-zero size,
+  /// return null from [builder], or set a [childCount].
+  ///
   /// The delegate wraps the children returned by this builder in
   /// [RepaintBoundary] widgets.
   final NullableIndexedWidgetBuilder builder;
@@ -383,6 +388,11 @@ class SliverChildBuilderDelegate extends SliverChildDelegate {
   ///
   /// If null, the number of children is determined by the least index for which
   /// [builder] returns null.
+  ///
+  /// May result in an infinite loop or run out of memory if [childCount] is null
+  /// and the [builder] always provides a zero-size widget (such as `Container()`
+  /// or `SizedBox.shrink()`). If possible, provide children with non-zero size,
+  /// return null from [builder], or set a [childCount].
   final int? childCount;
 
   /// Whether to wrap each child in an [AutomaticKeepAlive].