Same as https://github.com/facebook/react/issues/10103, but for the server renderer. You can look at implementation in https://github.com/facebook/react/pull/11168 and do something very similar in `ReactPartialRenderer.js`.
tagVerbatim: string,
  tagLowercase: string,
  props: Object,
  namespace: string,
  makeStaticMarkup: boolean,
  isRootElement: boolean,
): string {
  let ret = '<' + tagVerbatim;
  for (const propKey in props) {
    if (!props.hasOwnProperty(propKey)) {
      continue;
    }
    let propValue = props[propKey];
    if (propValue == null) {
      continue;
    }
    if (propKey === STYLE) {
      propValue = createMarkupForStyles(propValue);
    }
    let markup = null;
    if (isCustomComponent(tagLowercase, props)) {
      if (!RESERVED_PROPS.hasOwnProperty(propKey)) {
        markup = createMarkupForCustomAttribute(propKey, propValue);