private static void addExtension(io.swagger.v3.oas.annotations.media.Content annotationContent,
			MediaType mediaType, boolean openapi31) {
		if (annotationContent.extensions().length > 0) {
			Map<String, Object> extensions = AnnotationsUtils.getExtensions(openapi31, annotationContent.extensions());
			extensions.forEach(mediaType::addExtension);
		}
	}
Add extension.

@param annotationContent the annotation content
@param mediaType         the media type
@param openapi31         the openapi 31
springdoc-openapi-starter-common/src/main/java/org/springdoc/core/utils/SpringDocAnnotationsUtils.java