Overlay widgets in any context... only issue, hot reload is broken

local_overlay.dart

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:tuple/tuple.dart';
import 'package:uuid/uuid.dart';

class LocalOverlayScope extends StatefulWidget {
  const LocalOverlayScope({Key? key, required this.child}) : super(key: key);

  final Widget child;

  @override
  State<LocalOverlayScope> createState() => LocalOverlayScopeState();
}

class LocalOverlayScopeState extends State<LocalOverlayScope> {
  final _links = <String, Tuple3<LayerLink, Widget, _Params>>{};

  LayerLink registerWidget(String linkKey, Widget widget, _Params params) {
    return (_links[linkKey] ??= Tuple3(LayerLink(), widget, params)).item1;
  }

  void unregisterWidget(String linkKey) {
    _links.remove(linkKey);
  }

  @override
  void initState() {
    // would be nice to remove this build race
    WidgetsBinding.instance.addPostFrameCallback((_) => setState(() {}));
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Provider.value(
      value: this,
      child: Stack(
        children: [
          widget.child,
          for (final link in _links.entries)
            CompositedTransformFollower(
              key: ValueKey(link.key),
              link: link.value.item1,
              child: link.value.item2,
              showWhenUnlinked: link.value.item3.showWhenUnlinked,
              offset: link.value.item3.offset,
              targetAnchor: link.value.item3.targetAnchor,
              followerAnchor: link.value.item3.followerAnchor,
            ),
        ],
      ),
    );
  }
}

class LocalOverlayTarget extends StatefulWidget {
  LocalOverlayTarget({
    Key? key,
    required this.child,
    required this.follower,
    this.targetAnchor = Alignment.topCenter,
    this.followerAnchor = Alignment.bottomCenter,
    this.offset = Offset.zero,
    this.showWhenUnlinked = true,
  }) : super(key: key);

  final Widget child;

  final Widget follower;

  final Alignment targetAnchor;

  final Alignment followerAnchor;

  final Offset offset;

  final bool showWhenUnlinked;

  @override
  State<LocalOverlayTarget> createState() => _LocalOverlayTargetState();
}

class _LocalOverlayTargetState extends State<LocalOverlayTarget> {
  late final linkKey = Uuid().v4();

  late final scope = Provider.of<LocalOverlayScopeState>(context);

  late final _params = _Params(
    targetAnchor: widget.targetAnchor,
    followerAnchor: widget.followerAnchor,
    offset: widget.offset,
    showWhenUnlinked: widget.showWhenUnlinked,
  );

  // would be nice to update this when follower or params are updated,
  // because right now hot reload does not work
  late LayerLink link = scope.registerWidget(linkKey, widget.follower, _params);

  @override
  void dispose() {
    scope.unregisterWidget(linkKey);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return CompositedTransformTarget(
      link: link,
      child: widget.child,
    );
  }
}

class _Params {
  _Params({
    this.targetAnchor = Alignment.topCenter,
    this.followerAnchor = Alignment.bottomCenter,
    this.offset = Offset.zero,
    this.showWhenUnlinked = false,
  });

  final Alignment targetAnchor;

  final Alignment followerAnchor;

  final Offset offset;

  final bool showWhenUnlinked;
}

Internal ref: https://github.com/tonalfitness/mobile/pull/6285/files#diff-9ccadadfd9cc899e77dde8280f5e8b1f651a4a9353b09b8be34bed6cffc907a7

Internal ref: https://github.com/lukepighetti/vgl/blob/07f38e7216abf5df3177e463b488c7cdf08892a2/lib/features/architecture/overlay_composer.dart