For example, in one of the ways the OAuth2 specification can be used (called "password flow") it is required to send a `username` and `password` as form fields.

The <abbr title="specification">spec</abbr> requires the fields to be exactly named `username` and `password`, and to be sent as form fields, not JSON.

- ObjectType (default)
- LegacyObjectType (preserves existing deployments and older xl.json format)
- DeleteMarker (a versionId to capture the DELETE sequences implemented primarily for AWS spec compatibility)

A sample msgpack-JSON `xl.meta`, you can debug the content inside `xl.meta` using [xl-meta.go](https://github.com/minio/minio/tree/master/docs/debugging#decoding-metadata) program.

```json
{

import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A simplistic collection which implements only the bare minimum allowed by the spec, and throws
 * exceptions whenever it can.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public class MinimalCollection<E extends @Nullable Object> extends AbstractCollection<E> {

Por exemplo, em uma das maneiras que a especificação OAuth2 pode ser usada (chamada "fluxo de senha"), é necessário enviar um `username` e uma `password` como campos do formulário.

A <abbr title="specification – especificação">spec</abbr> exige que os campos sejam exatamente nomeados como `username` e `password` e sejam enviados como campos de formulário, não JSON.

        val tlsEquipPlan = planWithCurrentOrInitialConnectionSpec(connectionSpecs, sslSocket)
        val connectionSpec = connectionSpecs[tlsEquipPlan.connectionSpecIndex]

        // Figure out the next connection spec in case we need a retry.
        retryTlsConnection = tlsEquipPlan.nextConnectionSpec(connectionSpecs, sslSocket)

        connectionSpec.apply(sslSocket, isFallback = tlsEquipPlan.isTlsFallback)

    Hasher h1 = new NonStreamingVersion().newHasher();
    Hasher h2 = new NonStreamingVersion().newHasher();
    String s = new String(chars);
    // this is the correct implementation of the spec
    for (int i = 0; i < s.length(); i++) {
      h1.putChar(s.charAt(i));
    }
    h2.putUnencodedChars(s);
    assertEquals(h1.hash(), h2.hash());
  }

   */
  HTTP_1_0("http/1.0"),

  /**
   * A plaintext framing that includes persistent connections.
   *
   * This version of OkHttp implements [RFC 7230][rfc_7230], and tracks revisions to that spec.
   *
   * [rfc_7230]: https://tools.ietf.org/html/rfc7230
   */
  HTTP_1_1("http/1.1"),

  /**
   * Chromium's binary-framed protocol that includes header compression, multiplexing multiple

= vendor/github.com/container-storage-interface/spec licensed under: =

                                 Apache License
                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,

  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testCompute_presentNullToNull() {
    // The spec is somewhat ambiguous about this case, but the actual default implementation
    // in Map will remove a present null.
    initMapWithNullValue();
    assertNull(

  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testCompute_presentNullToNull() {
    // The spec is somewhat ambiguous about this case, but the actual default implementation
    // in Map will remove a present null.
    initMapWithNullValue();
    assertNull(