As mentioned in https://github.com/elastic/elasticsearch/pull/96216, `LuceneVerifyingIndexOutput` always copies the last chunk byte-by-byte. This might be a pretty big chunk. We should be able to copy all the bytes up to the start of the checksum in bulk (and then I guess bulk-copy the checksum too not that this matters so much).

In the same area, `LuceneVerifyingIndexOutput` is the only subclass of `VerifyingIndexOutput` and there's no need for it to be an inner class of `Store`. `VerifyingIndexInput` also doesn't need to be an inner class.
server/src/main/java/org/elasticsearch/index/store/Store.java
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.Lock;
import org.apache.lucene.store.NIOFSDirectory;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefBuilder;
import org.apache.lucene.util.Version;
import org.elasticsearch.ExceptionsHelper;
import org.elasticsearch.common.UUIDs;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.io.stream.BytesStreamOutput;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.common.logging.Loggers;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.common.lucene.store.ByteArrayIndexInput;
import org.elasticsearch.common.lucene.store.InputStreamIndexInput;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Setting.Property;
import org.elasticsearch.core.AbstractRefCounted;
import org.elasticsearch.core.IOUtils;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.core.RefCounted;
import org.elasticsearch.core.Streams;
import org.elasticsearch.core.TimeValue;
import org.elasticsearch.core.Tuple;
import org.elasticsearch.env.NodeEnvironment;
import org.elasticsearch.env.ShardLock;