Make an io call each time rather than sleeping for 10s

Test making io calls throughout the thread's lifecycles instead of
one io call then sleeping to better see the perf of parallelizing
multiple http calls.
Experimenting with thread count to determine threshold

Formula for calculating threads to maximize = # cores /
(1-busy-coefficient). One ruby process can only utilize a single core
so we'll always be capped to 1 / (1-busy-coefficient). The threshold of
diminishing returns on my mbp is about 8. This will likely be similar on
other machines b/c my mac has 4 cores but ruby only ever uses one.