Entropy generation feedback

[jcalfee]

Would you recommend a good callback implementation so I can get feedback during the entropy generation?

If you have used gpg to create a new key you should see some feedback about how much entropy they are collecting.

gpg --gen-key
...
Not enough random bytes available.  Please do some other work to give
the OS a chance to collect more entropy! (Need 264 more bytes)
.......+++++
+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
...........+++++
...

You can see, they are looping and printing more and more dots as more entropy is gathered.

So it would be nice to have a long running test run of more-entropy the prints something like the above. A simple callback would let the user format the output.

Fyi: I did run find / > /dev/null to get some good test results while gen-key was running. I could tell easily that it was stalled when this command was not running. That was convincing. I believe this would give a scene of how well the algorithm is working.