When retrieving UIDL with POP, data sometimes goes missing.

Hello,

Thank you for your continuous contributions to Ruby. I am using this library for work, and I have encountered a peculiar issue where UIDLs are sometimes missing.

I attempted to address this with the following patch:

diff --git a/lib/net/pop.rb b/lib/net/pop.rb
index d4ee8f8..d56a270 100644
--- a/lib/net/pop.rb
+++ b/lib/net/pop.rb
@@ -969,6 +969,7 @@ module Net
           getok('UIDL')
           table = {}
           @socket.each_list_item do |line|
+            pp "bad size #{line} #{line.split(' ').size}" if line.split(' ').size != 2
             num, uid = line.split(' ')
             table[num.to_i] = uid
           end

The results were as follows:

"bad size 588 UID794684-1450674668\r\n" + "589 UID794685-1450674668 4"
"bad size 3789 UID797886-1450674668\r\n" + "3790 UID797887-1450674668 4"
"bad size 7885 UID801982-1450674668\r\n" + "7886 UID801983-1450674668 4"

It seems that the delimiter is being ignored during the reading process. Although it appears that the socket is implemented to read up to \r\n as seen here:
https://github.com/ruby/ruby/blob/c0938fd24c927954dbe5d42e70844b6a89516786/lib/net/protocol.rb#L387

However, it seems this is being ignored. This is quite peculiar, and I am wondering if you have any ideas about this issue. If not, I am considering some potential solutions.

Thank you for your assistance.

Start in lib/net/pop.rb around the UIDL retrieval code and compare its line handling with the referenced reader in lib/net/protocol.rb at line 387. Reproduce the reported multi-entry behavior and determine why a UIDL record can combine adjacent lines; done means UIDL retrieval retains every record without losing entries.