public static String getAddressFirst(InetSocketAddress inetSocketAddress, String defaultAddress) {
        String address = getAddressFirst(inetSocketAddress);
        if (address == null) {
            return defaultAddress;
        }
        return address;
    }
Returns the String form of the IP address of the given {@link InetSocketAddress}, or the hostname
if it has not been resolved. Returns {@code defaultAddress} if neither can be retrieved.

<p>This <b>does not</b> trigger a DNS lookup if the address has not been resolved yet by simply
returning the hostname.

@param inetSocketAddress the socket address in which to retrieve the address from
@param defaultAddress    the value to return if neither the string form of the address nor the
                         hostname can be found
@return  the String representation of the address or the hostname, or {@code defaultAddress} if neither
         can be found.

@see InetSocketAddress#isUnresolved()
agent-module/bootstraps/bootstrap-core/src/main/java/com/navercorp/pinpoint/bootstrap/plugin/util/SocketAddressUtils.java