public RetryStrategy checkoutRetryStrategy(Throwable throwable) {
    for (RetryMapping mapping : retryMappings) {
      if (mapping.matches(throwable)) {
        return mapping.getStrategy();
      }
    }
    return defaultRetryStrategy;
  }
Returns the best {@link RetryStrategy} for a given Throwable. If there are no matches, returns
the default RetryStrategy.

Right now it just looks at the message in the Throwable and tries to find a matching regex in
its internal library.  Later on it will use more and more of the Throwable to make a decision.
portability-types-transfer/src/main/java/org/datatransferproject/types/transfer/retry/RetryStrategyLibrary.java