Xamarin.Behaviors File not found exception

I am working on Xamarin Forms and am using Xamarin.Forms.Behaviors version 1.3.1, given below is my code

In the content page root header i have added the namespace for Behaviors and it works fine

xmlns:b="clr-namespace:Xamarin.Behaviors;assembly=Xamarin.Behaviors"

I have added behavior in the search bar text change event but I am getting crash there attached is the screenshot for the same

 <SearchBar VerticalOptions="EndAndExpand"  
           x:Name="srcBar" Placeholder="Search"
           Text="{Binding SearchText, Mode=TwoWay}"
           > 

           <b:Interaction.Behaviors>
              <b:BehaviorCollection>
                <b:EventToCommand EventName="TextChanged" 
                Command="{Binding searchButtonCommand}" />
              </b:BehaviorCollection>
            </b:Interaction.Behaviors>

           </SearchBar>

I have added the NuGet package for the same as well and I am not able to find the issue here as whats wrong please help.