Exposing asynchronous features to client code: Windows Phone 7

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    x:Class="BonusBits.CodeSamples.WP7.ThreadingPage"
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    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
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    Orientation="Portrait"
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                x:Name="ApplicationTitle"
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                x:Name="PageTitle"
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        <!--ContentPanel - place additional content here-->
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            x:Name="ContentPanel"
            Grid.Row="1"
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                IsEnabled="{Binding Path=CanStart}"
                Height="72"
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                Width="160">
                <Button.Content>
                    <StackPanel
                        Orientation="Horizontal">
                        <TextBlock
                            Text="Start"
                            Margin="0,0,15,0" />
                        <Rectangle
                            Name="rectangle"
                            Fill="Gray"
                            Visibility="{Binding Path=CanExecuteWithSyncIO,
                                            Converter={StaticResource booleanToVisibilityConverter},
                                            ConverterParameter=!}"
                            HorizontalAlignment="Center"
                            VerticalAlignment="Center"
                            Width="15"
                            Height="15">
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                </Button.Content>
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                Content="Sync I/O"
                Height="72"
                HorizontalAlignment="Left"
                Margin="12,6,0,0"
                Name="CanExecuteWithSyncIO"
                VerticalAlignment="Top" />
            <RadioButton
                Content="Delegate's BeginInvoke"
                Height="72"
                HorizontalAlignment="Left"
                Margin="12,84,0,0"
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                VerticalAlignment="Top" />
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                Margin="12,0,0,373"
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                VerticalAlignment="Bottom" />
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                Width="276"
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    </Grid>
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