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
void match(LogEvent event);
        void assertMatched();
    }
    public abstract static class AbstractEventExpectation implements LoggingExpectation {
        protected final String name;
        protected final String logger;
        protected final Level level;
        protected final String message;
        volatile boolean saw;
        public AbstractEventExpectation(String name, String logger, Level level, String message) {
            this.name = name;
            this.logger = logger;
            this.level = level;
            this.message = message;