[ruby-dev:30126] net/pop error in Ruby 1.9

助田です。
Net::POP3.start で NoMethodError がでます。

$ cat x.rb
require 'net/pop'
pwd = 'XXXXX'
Net::POP3.start( 'SERVER', 110, 'USER', pwd ) do |ses|
end

$ ruby19 x.rb
/usr/local/lib/ruby/1.9/net/protocol.rb:66:in `closed?': \
undefined method `closed?' for true:TrueClass (NoMethodError)
        from /usr/local/lib/ruby/1.9/net/pop.rb:575:in `do_finish'
        from /usr/local/lib/ruby/1.9/net/pop.rb:510:in `ensure in start'
        from /usr/local/lib/ruby/1.9/net/pop.rb:510:in `start'
        from /usr/local/lib/ruby/1.9/net/pop.rb:382:in `start'
        from x.rb:3:in `<main>'

$ ruby19 -v
ruby 1.9.0 (2007-01-10 patchlevel 0) [i686-linux]

  助田雅紀