presto-client/src/main/java/io/prestosql/client/JsonResponse.java/JsonResponse/toString
class JsonResponse:    @Override
    public String toString()
    {
        return toStringHelper(this)
                .add("statusCode", statusCode)
                .add("statusMessage", statusMessage)
                .add("headers", headers.toMultimap())
                .add("hasValue", hasValue)
                .add("value", value)
                .omitNullValues()
                .toString();
    }