MockMiddlewareInStartup.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
  //other configurations removed for brevity.
  
  ImpostersAsMockConfiguration mockConfiguration =
          new ImpostersAsMockConfiguration(new MockImpostersBuilder()
                                                   .CreateMockImposters(),
                                           new MocksDataStore()
                                                   .Create());

  app.UseMockImposters(mockConfiguration);
}