instance.setHeaderFields((CollectionProperty)getProperty(SmtpSampler.HEADER_FIELDS));
message = instance.prepareMessage();
if (getPropertyAsBoolean(MESSAGE_SIZE_STATS)) {
// calculate message size
CounterOutputStream cs = new CounterOutputStream();
message.writeTo(cs);
res.setBytes(cs.getCount());
} else {
res.setBytes(-1);
}
} catch (AddressException ex) {