code: public static String checkAuthority(String authority) {
      URI uri = authorityToUri(authority);
      checkArgument(uri.getHost() != null, "No host in authority '%s'", authority);
      checkArgument(uri.getUserInfo() == null,
          "Userinfo must not be present on authority: '%s'", authority);
      return authority;
    }
docs: Verify {@code authority} is valid for use with gRPC. The syntax must be valid and it must not
  include userinfo.
  
  @return the {@code authority} provided