Commit 1e0a518d6548 added a new NFS mount option "nconnect".
This patch adds information on this option to the man page.
It also adds an IMPLEMENTATION section that explains how
the default I/O size is determined and that "nfsstat -m" can
be used to find out what option settings are actually in use.
This is a content change.
Reviewed by: gbe (manpages)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D31135
4488c8c34b