static short parseHextet(String ipPart) {
    // Note: we already verified that this string contains only hex digits.
    int hextet = Integer.parseInt(ipPart, 16);
    if (hextet > 0xffff) {
      throw new NumberFormatException();
    }
    return (short) hextet;
  }
Adapted from code in {@code com.google.common.net.InetAddresses.ipStringToBytes}. This version
separates detection from parsing and checks more carefully about embedded addresses.
zipkin/src/main/java/zipkin2/Endpoint.java