You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

### Installing xl-meta

To install, [Go](https://golang.org/dl/) must be installed. Once installed, execute this to install the binary:

```bash
go install github.com/minio/minio/docs/debugging/xl-meta@latest
```

### Using xl-meta

 * transitions form a <a href="http://en.wikipedia.org/wiki/Directed_acyclic_graph">DAG</a>,
 * therefore every method of the listener will be called at most once. N.B. The {@link State#FAILED}
 * and {@link State#TERMINATED} states are terminal states, once a service enters either of these
 * states it cannot ever leave them.
 *
 * <p>Implementors of this interface are strongly encouraged to extend one of the abstract classes

### Creating the `Settings` only once with `lru_cache`

Reading a file from disk is normally a costly (slow) operation, so you probably want to do it only once and then reuse the same settings object, instead of reading it for each request.

But every time we do:

```Python
Settings()
```

				break
			}

			if !rule.Expiration.IsDaysNull() {
				// Specifying the Days tag will automatically perform ExpiredObjectDeleteMarker cleanup
				// once delete markers are old enough to satisfy the age criteria.
				// https://docs.aws.amazon.com/AmazonS3/latest/userguide/lifecycle-configuration-examples.html

  /*
   * TODO(b/242884182): Figure out why this helps produce the same class file when we compile most
   * of common.collect a second time with the results of the first compilation on the classpath. Or
   * just back this out once we stop doing that (which we'll do after our internal GWT setup
   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

 * @author Miles Barr
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public interface LineProcessor<T extends @Nullable Object> {

  /**
   * This method will be called once for each line.
   *
   * @param line the line read from the input, without delimiter
   * @return true to continue processing, false to stop
   */

  /*
   * TODO(b/242884182): Figure out why this helps produce the same class file when we compile most
   * of common.collect a second time with the results of the first compilation on the classpath. Or
   * just back this out once we stop doing that (which we'll do after our internal GWT setup
   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

      sizeRemaining -= count;
      hashMultiset.add(value, count);
      linkedHashMultiset.add(value, count);
      treeMultiset.add(value, count);
    }

    // TODO(kevinb): convert to assert once benchmark tests enable asserts by default
    Preconditions.checkState(hashMultiset.size() == size);
  }

  @Benchmark
  int hashMultiset(int reps) {
    int sum = 0;
    for (int i = 0; i < reps; i++) {

      sizeRemaining -= count;
      hashMultiset.add(value, count);
      linkedHashMultiset.add(value, count);
      treeMultiset.add(value, count);
    }

    // TODO(kevinb): convert to assert once benchmark tests enable asserts by default
    Preconditions.checkState(hashMultiset.size() == size);
  }

  @Benchmark
  int hashMultiset(int reps) {
    int sum = 0;
    for (int i = 0; i < reps; i++) {