SharedVariable2.cs

public void Execute(IServiceProvider serviceProvider)
{
   // Obtain the tracing service
   ITracingService tracingService = (ITracingService)serviceProvider.GetService(typeof(ITracingService));

   // Obtain the execution context from the service provider.  
    IPluginExecutionContext executionContext = (IPluginExecutionContext)
    serviceProvider.GetService(typeof(IPluginExecutionContext))
    
    bool myFlag = false;

    //Check existence of shared variable and fetch the value from executionContext
    if (executionContext != null && executionContext.SharedVariables.ContainsKey("MyFlag"))
    {
        myFlag = (bool)executionContext.SharedVariables.ContainsKey("MyFlag");
    }   
    
    //if(myFlag)
    // your logic
    //else
    // your logic
}