function getURLType(source) {
  if (source[0] === "/") {
    if (source[1] === "/") {
      return "scheme-relative";
    }

    return "path-absolute";
  }

  if (IS_NATIVE_WIN32_PATH.test(source)) {
    return "path-absolute";
  }

  return ABSOLUTE_SCHEME.test(source) ? "absolute" : "path-relative";
}
@param {string} source
@returns {"absolute" | "scheme-relative" | "path-absolute" | "path-absolute"}