Hash fuzzed input to detect duplicates?

When generating random values from a fuzzer, there is no guarantee that each one will be unique. You may ask for 100 cases but get less. It may be possible you get *much* less.

One solution is to hash each input, store the hashes, and reject inputs with a duplicate hash. We'd need to fail the test after some number of failed attempts to create distinct inputs, perhaps `max 20 (2*numberOfRequestedRuns)`.

Since we'd want a designated union type tag for this failure condition, it makes sense to do this while we're doing a major revision.

Is there any interest in exploring this idea?