Known issues/TODO (for steady-state)

- Replace the test script with a better one
  - Add test cases for the new check_interval option
  - Parse debug=steadystate output to check calculations

- Instead of calculating `intervals` every time, calculate it once and stash it
  somewhere

- Add the time unit to the ss_dur and check_interval variable names to reduce
  possible confusion

- Better documentation for output

- Report read, write, trim IOPS/BW separately

- Semantics for the ring buffer ss->head are confusing. ss->head points
  to the beginning of the buffer up through the point where the buffer
  is filled for the first time. afterwards, when a new element is added,
  ss->head is advanced to point to the second element in the buffer. if
  steady state is attained upon adding a new element, ss->head is not
  advanced so it actually does point to the head of the buffer.