I got it !
The $lines parameter in OpenMessage says how large the chunks will be when one calls GetMessage.
Question:  IN using the streams handler in POP3_class:
$message_file='pop3://'.$user.':'.$password.'@localhost/'.$message.		'?debug='.$debug.'&html_debug='.$html_debug.'&realm='.$realm.'&workstation='.$workstation.		'&apop='.$apop.'&authentication_mechanism='.$authentication_mechanism;
	
if the ISPs mail server is 'pop.mailserver.com', and
my account is '
[email protected]', and
my password is 'password',  
what would the form of the request be ?
$message_file='pop3://'.$user.':'.$password.'@mydomain.com:110/'.$message.
'?debug='.$debug.'&html_debug='.$html_debug.'&realm='.$realm.'&workstation='.$workstation.		'&apop='.$apop.'&authentication_mechanism='.$authentication_mechanism;