Ability to monitor progression of hashing

[luke-jr]

Some way to determine which extranonce2s have been used would be useful, and also specify to skip N extranonce2s in a job.

For example, take the following scenario:

1. Pool 0 is active, so we send its job
2. We switch to pool 1 after 15 seconds, and send its job.
3. We switch back to pool 0 before its job has changed. We are now sending the original job again and MM repeats duplicate work!