SharedVariable3.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))
    
    if(mycondition == true)
      executionContext.SharedVariables.Add("MyFlag", true)
    else
      executionContext.SharedVariables.Add("MyFlag", false)

}