Show HN: A naive SHA265 collision finder in Rust

I don't really expect to find one (I won't have the results for an 8-character input until tomorrow afternoon sometime, and 9-character inputs around mid-March if I don't reboot my machine), but thought it would be an interesting experiment - and hey, blind luck can always play a part :) Plus I got to learn a little Rust!

At 1 million hashes per second (assuming that speed remains fairly constant - which it probably won't), it would take my machine around 2.5 trillion years to get through the entire 64^16 set! Once I get to source strings that are 20 characters long, I should have about a 25% chance of having found a collision