@Override
    public String toString() {
        final ToStringHelper stringHelper = MoreObjects.toStringHelper(this)
                                                       .add("specification", specification);
        if (baseOption == BaseOption.fixed) {
            stringHelper.add("fixedDelayMillis", fixedDelayMillis);
        } else if (baseOption == BaseOption.random) {
            stringHelper.add("randomMinDelayMillis", randomMinDelayMillis)
                        .add("randomMaxDelayMillis", randomMaxDelayMillis);
        } else {
            stringHelper.add("initialDelayMillis", initialDelayMillis).add("maxDelayMillis", maxDelayMillis)
                        .add("multiplier", multiplier);
        }

        stringHelper.add("minJitterRate", minJitterRate).add("maxJitterRate", maxJitterRate);
        if (maxAttemptsConfigured) {
            stringHelper.add("maxAttempts", maxAttempts);
        }

        return stringHelper.toString();
    }
Returns a newly-created {@link Backoff} based on the properties of this spec.
core/src/main/java/com/linecorp/armeria/client/retry/BackoffSpec.java