private async void Switch_Toggled(object sender, ToggledEventArgs e)
        {
            Tasks task = (sender as Switch).BindingContext as Tasks;
            await ApiManager.UpdateTasksFromListAsync(task);
        }

<ListView x:Name="lvwDetailPage" SeparatorVisibility="None">
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="70" />
                            <ColumnDefinition />
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition />
                        </Grid.RowDefinitions>

                        <Switch IsToggled="{Binding completed}" Grid.Column="0" Toggled="Switch_Toggled" />
                        <Label Grid.Column="1" Text="{Binding title}" TextColor="#212121" VerticalOptions="Center" Margin="10,0" />

                    </Grid>
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>