default Optional<TenantDefinition> extract(final RequestContext requestContext) {
        val request = (HttpServletRequest) requestContext.getExternalContext().getNativeRequest();
        return extract(request);
    }
Extract tenant id from request context.

@param requestContext the request context
@return the tenant id
api/cas-server-core-api-multitenancy/src/main/java/org/apereo/cas/multitenancy/TenantExtractor.java