The first line's status number is the number of identifiers returned or less
than zero if an error occurred. Each of the following lines contains the
-update time as an epoch value and the identifier, separated by a space.
+update time as an epoch value and the identifier, separated by a space. The
+update time is the time of the last value, as provided by the collecting
+instance and may be very different from the time the server consideres to be
+"now".
Example:
-> | LISTVAL
-> | PUTNOTIF type=temperature severity=warning time=1201094702 message=The roof is on fire!
<- | 0 Success
+=item B<FLUSH> [B<timeout=>I<Timeout>] [B<plugin=>I<Plugin> [...]]
+
+Flushes all cached data older than I<Timeout> seconds. If no timeout has been
+specified, it defaults to -1 which causes all data to be flushed. B<timeout>
+may be specified multiple times - each occurrence applies to plugins listed
+afterwards.
+
+If specified, only specific plugins are flushed. Otherwise all plugins
+providing a flush callback are flushed.
+
+Example:
+ -> | FLUSH
+ <- | 0 Done
+
=back
=head2 Identifiers