[BUG] Symbol added through the SymbolManager cannot be positionned above other layers

[andynewman10]

Platforms

web

Version of flutter maplibre_gl

0.24.1

Bug Description

It is not possible to add a symbol using the SymbolManager and have this symbol be displayed on top of other layers that have been previously added. This seems odd and counter intuitive.

maplibre.MapLibreMap(
  onMapCreated: (maplibre.MapLibreMapController controller) {
    // For some reason, when I add my source and layers here, they are not displayed,
    // so I am adding them in onStyleLoadedCallback instead.
  },
  onStyleLoadedCallback: () async {
    // Add a source and layers using this source here (making sure everything is awaited)
    // This works fine.
    
    // Register icon '_markerIconName' (again, awaited)

    // Add a symbol
    final symbol = maplibre.Symbol(
        symbolId,
        buildSymbolOptions(
            geometry: maplibre.LatLng(ll.latitude, ll.longitude),
            iconImage: _markerIconName,
            iconSize: 1.2,
            zIndex: 1000));
    await _mapsController!.symbolManager!.add(symbol);

    // At this point, the symbol is successfully displayed, but behind the layers added further up in this code block
  }

This works fine, but the added symbol is always displayed behind the added layers.

Is there a way to have this symbol displayed above everything else? Do I need to add a custom layer or is there a way to somehow "delay" the creation of the SymbolManager ?

Steps to Reproduce

Use above code.

Expected Results

Defining a symbol using the SymbolManager should make it possible to display this symbol above everything else. This scenario is quite common, I believe, and - maybe I am mistaken - I expected the SymbolManager to be a handy way to quickly add a symbol, again, typically above all other layers. Handy way = without going through the effort of adding a custom layer with eg., just one symbol in this layer.

Actual Results

The SymbolManager (and probably associated internal layer) is always displayed behind previously-added layers.
The API (at least the web api) does not provide a way to set the z-index of the SymbolManager layer, as far as I can tell.

Code Sample

See above.