* Fetch metadata of pending messages sent to the {@code xtaIdentifier}.
* Fetch metadata of pending messages sent to the {@code xtaIdentifier}. The returned listing contains at most
* The returned listing contains at most {@link de.ozgcloud.xta.client.config.XtaClientConfig#getMaxListItems() maxListItems} messages.
* {@link de.ozgcloud.xta.client.config.XtaClientConfig#getMaxListItems() maxListItems} messages. Use the {@code requestId} to
* Use the {@code requestId} to {@link #close(String) close} pending messages.
* {@link #close(String) close} pending messages. To fetch the next messages, use {@link #getNextMessagesMetadata(String)}. Note that
* To fetch the next messages, use {@link #getNextMessagesMetadata(String)}.
* {@code xtaIdentifier} has to be configured as a
* Note that {@code xtaIdentifier} has to be configured as a {@link de.ozgcloud.xta.client.config.XtaClientConfig#getClientIdentifiers() clientIdentifiers}.