presto-spi/src/main/java/io/prestosql/spi/HostAddress.java/HostAddress/toString
class HostAddress:    @JsonValue
    @Override
    public String toString()
    {
        StringBuilder builder = new StringBuilder(host.length() + 7);
        if (host.indexOf(':') >= 0) {
            builder.append('[').append(host).append(']');
        }
        else {
            builder.append(host);
        }
        if (hasPort()) {
            builder.append(':').append(port);
        }
        return builder.toString();
    }