code: public static Endpoint parse(String authority) {
          requireNonNull(authority, "authority");
          if (authority.startsWith("group:")) {
              return ofGroup(authority.substring(6));
          }
  
          final HostAndPort parsed = HostAndPort.fromString(authority).withDefaultPort(0);
          return create(parsed.getHost(), parsed.getPort());
      }
docs: Parse the authority part of a URI. The authority part may have one of the following formats:
  <ul>
  <li>{@code "group:<groupName>"} for a group endpoint</li>
  <li>{@code "<host>:<port>"} for a host endpoint</li>
  <li>{@code "<host>"} for a host endpoint with no port number specified</li>
  </ul>
  An IPv4 or IPv6 address can be specified in lieu of a host name, e.g. {@code "127.0.0.1:8080"} and
  {@code "[::1]:8080"}.