private long calcDeadlineMs(long now, Integer optionTimeoutMs) {
        if (optionTimeoutMs != null)
            return now + Math.max(0, optionTimeoutMs);
        return now + defaultApiTimeoutMs;
    }
Get the deadline for a particular call.

@param now               The current time in milliseconds.
@param optionTimeoutMs   The timeout option given by the user.

@return                  The deadline in milliseconds.
clients/src/main/java/org/apache/kafka/clients/admin/KafkaAdminClient.java