+=head1 PERFORMANCE NOTES
+
+L<Inline::C> is required, lei runs as a background daemon to reduce
+startup costs and can provide real-time L<kqueue(2)>/L<inotify(7)>
+Maildir monitoring. L<IO::KQueue> (p5-IO-KQueue on FreeBSD) and
+L<Linux::Inotify2> (liblinux-inotify2-perl and perl-Linux-Inotify2 in
+.deb and .rpm-based distros, respectively) are recommended.
+
+L<Socket::MsgHdr> is optional (libsocket-msghdr-perl in Debian),
+and further improves startup performance. Its effect is most felt
+when using shell completion.
+
+=head1 BASH COMPLETION
+
+Preliminary Bash completion for lei is provided in
+C<contrib/completion/>. Contributions adding support for other
+shells, as well as improvements to the existing Bash completion, are
+welcome.
+