code: public CorsConfig build() {
          if (preflightHeaders.isEmpty() && !noPreflightHeaders) {
              preflightHeaders.put(HttpHeaderNames.DATE, DateValueGenerator.INSTANCE);
              preflightHeaders.put(HttpHeaderNames.CONTENT_LENGTH, new ConstantValueGenerator("0"));
          }
          return new CorsConfig(this);
      }
docs: Builds a {@link CorsConfig} with settings specified by previous method calls.
  
  @return {@link CorsConfig} the configured CorsConfig instance.