Benchmark: timing 10000 iterations of hasheq, items, slices...
    hasheq:  3 wallclock secs ( 2.97 usr +  0.00 sys =  2.97 CPU) @ 3367.00/s (n=10000)
     items:  4 wallclock secs ( 4.18 usr +  0.00 sys =  4.18 CPU) @ 2392.34/s (n=10000)
    slices:  3 wallclock secs ( 2.96 usr +  0.00 sys =  2.96 CPU) @ 3378.38/s (n=10000)
         Rate  items hasheq slices
items  2392/s     --   -29%   -29%
hasheq 3367/s    41%     --    -0%
slices 3378/s    41%     0%     --