DefaultBackoff always returns 0 seconds.

Do keeps trying the function until the second argument returns false, or no error is returned.

ExponentialJitterBackoff returns ever increasing backoffs by a power of 2 with +/- 0-33% to prevent sychronized reqests.

IsMaxRetries checks whether the error is due to hitting the maximum number of retries or not.

MaxRetries is the maximum number of retries before bailing.

BackoffStrategy is used to determine how long a retry request should wait until attempted.

Func represents functions that can be retried.