setIfAbsent return value is unclear

[ML-Marco]

The Javadoc for org.springframework.data.redis.core.ValueOperations#setIfAbsent(K, V) is:

	/**
	 * Set the {@code value} for {@code key} if {@code key} is absent.
	 *
	 * @param key must not be {@literal null}.
	 * @param value must not be {@literal null}.
	 * @return {@literal null} when used in pipeline / transaction.
	 * @see <a href="https://redis.io/commands/set">Redis Documentation: SET</a>
	 */

This does not mention what the method returns when not used in pipeline / transaction.

[AzazelSensei]

#3415