A user (on 7.17.7) reported to me a situation where they were attempting to delete a snapshot and would get the log message `deleting snapshots [snapshot-test] from repository [my-snapshots]` but then no further messages at `INFO` or above; enabling some internal logging indicated some low-level timeouts:

```
[DEBUG][com.amazonaws.latency    ] [instance-0123456789] MaxRetriesExceeded=[true], ServiceName=[Amazon S3], ServiceEndpoint=[https://REDACTED/], Exception=[java.net.SocketTimeoutException: Read timed out, java.net.SocketTimeoutException: Read timed out, java.net.SocketTimeoutException: Read timed out, java.net.SocketTimeoutException: Read timed out],...
```

This was enough for the user to go and investigate some performance issues in their repository, but I find the lack of logging concerning. Eventually the cluster state contains no ongoing snapshot deletion, but there is nothing in the logs to indicate that anything didn't work. The deletion API request had already timed out by this point so we can't return an error that way either. I'm opening this issue to make sure we investigate the missing logging.
server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java
}
    }
    private static ShardGenerations buildGenerations(SnapshotsInProgress.Entry snapshot, Metadata metadata) {
        ShardGenerations.Builder builder = ShardGenerations.builder();
        if (snapshot.isClone()) {
            snapshot.shardsByRepoShardId().forEach((key, value) -> builder.put(key.index(), key.shardId(), value));
        } else {
            snapshot.shardsByRepoShardId().forEach((key, value) -> {
                final Index index = snapshot.indexByName(key.indexName());
                if (metadata.index(index) == null) {
                    assert snapshot.partial() : "Index [" + index + "] was deleted during a snapshot but snapshot was not partial.";
                    return;
                }
                builder.put(key.index(), key.shardId(), value);
            });
        }
        return builder.build();
    }
    private static Metadata metadataForSnapshot(SnapshotsInProgress.Entry snapshot, Metadata metadata) {
        final Metadata.Builder builder;
        if (snapshot.includeGlobalState() == false) {
            
            builder = Metadata.builder();
            for (IndexId index : snapshot.indices().values()) {
                final IndexMetadata indexMetadata = metadata.index(index.getName());
                if (indexMetadata == null) {
                    assert snapshot.partial() : "Index [" + index + "] was deleted during a snapshot but snapshot was not partial.";
                } else {
                    builder.put(indexMetadata, false);
                }