nfsstat --sleep=#

[Kevin Constantine <Kevin.Constantine-FfNkGbSheRGpB8w63BLUukEOCMrvLtNR@public.gmane.org>]

I'd really like to have a way to output the nfsstat counters at regular 
intervals (every 3 seconds) where the output is the difference between 3 
seconds ago and now.  Frequently I'll run a test and want to watch the 
nfs call profile throughout the course of the test.

Does something like this already exist?
Are there objections to seeing a feature like this?

I'm thinking something like:
nfsstat --sleep=1

  nfs v3 call:   Server   Client
        total:        0     3476
         null:        0        0
      getattr:        0     1679
      setattr:        0        0
       lookup:        0      839
       access:        0      839
     readlink:        0        0
         read:        0        0
        write:        0        0
       create:        0        0
        mkdir:        0        0
      symlink:        0        0
        mknod:        0        0
       remove:        0        0
        rmdir:        0        0
       rename:        0        0
         link:        0        0
      readdir:        0        0
  readdirplus:        0        0
       fsstat:        0      119
       fsinfo:        0        0
     pathconf:        0        0
       commit:        0        0