We limit the number of concurrent blob downloads per node and per recovery, but if a user configures too many concurrent recoveries they may run out of per-node download permits which yields the following message:

> Unable to acquire permit to use snapshot files during recovery, this recovery will recover index files from the source node. Ensure snapshot files can be used during recovery by setting [indices.recovery.max_concurrent_snapshot_file_downloads] to be no greater than [25]

The `[25]` here is wrong, the 25 permits are shared across all inbound recoveries so we should divide the suggested value by `cluster.routing.allocation.node_concurrent_incoming_recoveries`. In extreme cases the user may have configured so many concurrent recoveries that the only reasonable limit is zero, and in that case we should suggest setting `indices.recovery.use_snapshots: false` instead.


test/framework/src/main/java/org/elasticsearch/test/MockLogAppender.java
private final Class<? extends Exception> clazz;
        private final String exceptionMessage;
        public ExceptionSeenEventExpectation(
            final String name,
            final String logger,
            final Level level,
            final String message,
            final Class<? extends Exception> clazz,
            final String exceptionMessage
        ) {
            super(name, logger, level, message);
            this.clazz = clazz;
            this.exceptionMessage = exceptionMessage;
        }
        @Override
        public boolean innerMatch(final LogEvent event) {
            return event.getThrown() != null
                && event.getThrown().getClass() == clazz
                && event.getThrown().getMessage().equals(exceptionMessage);
        }
    }
    public static class PatternSeenEventExpectation implements LoggingExpectation {