Chore/fix solara notebook (#254)

* naming conflict with pandas and polars dataframe both named df

* updates to solara demo,  threaded dataframe fetching

example-notebooks/Solara-Buckaroo.ipynb

@@ -81,10 +81,10 @@
    "source": [
     "import polars as pl\n",
     "from buckaroo.solara_buckaroo import SolaraPolarsDFViewer, SolaraPolarsBuckarooWidget\n",
-    "df = pl.DataFrame({'a':[10,20]})\n",
+    "pldf = pl.DataFrame({'a':[10,20]})\n",
     "@solara.component\n",
     "def Page():\n",
-    "    bw = SolaraPolarsDFViewer(df=df, pinned_rows=[])\n",
+    "    bw = SolaraPolarsDFViewer(df=pldf, pinned_rows=[])\n",
     "display(Page())"
    ]
   },
@@ -105,7 +105,7 @@
    },
    "outputs": [],
    "source": [
-    "cb_trips_df = pd.read_csv(\"https://github.com/paddymul/buckaroo-data/raw/main/cb_data/2016-04.csv\")\n"
+    "cb_trips_df = pd.read_csv(\"https://github.com/paddymul/buckaroo-data/raw/main/cb_data/2016-04.csv\")"
    ]
   },
   {
@@ -166,7 +166,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "74ff8e28-56ed-4cf8-9473-b88f9b047178",
+   "id": "48f11839-2fe0-454b-b616-d82d5fcabf38",
    "metadata": {
     "tags": []
    },
@@ -183,8 +183,15 @@
     "@solara.component\n",
     "def Page():\n",
     "    solara.Select(label=\"df_name\", value=df_name, values=dataframe_names)\n",
-    "    active_df = pl.read_parquet(url_base+df_name.value)\n",
-    "    bw = SolaraPolarsDFViewer(active_df)\n",
+    "\n",
+    "    @solara.lab.use_task(dependencies=[df_name.value])\n",
+    "    def read_df():\n",
+    "        return pl.read_parquet(url_base+df_name.value)\n",
+    "\n",
+    "    solara.ProgressLinear(read_df.pending)\n",
+    "    if read_df.latest is not None:\n",
+    "        with solara.Div(style={\"opacity\": 0.3 if read_df.pending else 1.0}):\n",
+    "            SolaraPolarsDFViewer(read_df.latest)\n",
     "\n",
     "    solara.Markdown(f\"**Selected**: {df_name.value}\")\n",
     "display(Page())"