@SafeVarargs
    static <T extends Response> RetryRuleWithContent<T> of(RetryRuleWithContent<T>... retryRules) {
        requireNonNull(retryRules, "retryRules");
        checkArgument(retryRules.length > 0, "retryRules can't be empty.");
        if (retryRules.length == 1) {
            return retryRules[0];
        }
        return of(ImmutableList.copyOf(retryRules));
    }
Returns a {@link RetryRuleWithContent} that combines the specified {@code retryRules}.
core/src/main/java/com/linecorp/armeria/client/retry/RetryRuleWithContent.java