Optional Keyword Arguments:
  max_retries:        number of retries after which GiveUpRetryError will be raised
  max_sleep:          cumulated sleep (backoff) after which GiveUpRetryError will be raised
  on_retry:           function to invoke _before_ each retry
  init_backoff:       initial backoff that will potentially increase afterwards
  backoff_multiplier: multiplication factor between consecutive backoffs
                      set it to  1 for constant backoff
                      set it to >1 for exponential backoff