docs: protected Environment startEnvironment(ApplicationContext applicationContext) {
          if (!applicationContext.isRunning()) {
              if (this instanceof PropertySource) {
                  applicationContext.getEnvironment().addPropertySource((PropertySource) this);
              }
  
              return applicationContext
                      .start()
                      .getEnvironment();
          } else {
              return applicationContext.getEnvironment();
          }
      }