## Description of `xl.meta`

`xl.meta` is a new self describing backend format used by MinIO to support AWS S3 compatible versioning.
This file is the source of truth for each `version` at rest. `xl.meta` is a msgpack file serialized from a
well defined data structure. To understand `xl.meta` here are the few things to start with

`xl.meta` carries first 8 bytes an XL header which describes the current format and the format version,

  client_job->mutable_tasks()->insert(
      {0, absl::StrCat("localhost:", client_port)});
  server_def.set_job_name("localhost");
  auto serialized = server_def.SerializeAsString();
  TFE_ContextSetServerDef(ctx, 0, serialized.data(), serialized.size(), status);
  EXPECT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);

  EXPECT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);

 * (We have made some trivial local modifications (commented out
 * uncompilable code).)
 */

package com.google.common.util.concurrent;

import static com.google.common.testing.SerializableTester.reserialize;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

import com.google.common.annotations.GwtIncompatible;

  /**
   * An instance created in {@link #readObject} to be returned from {@link #readResolve}. This field
   * is used only by those methods, and it is never set in a "normal" instance.
   *
   * <p>This class needs to write deserialized data into fields that are {@code final transient}.
   * Such writes will become impossible to perform in {@link #readObject} after JEP 500. Instead, we

			if err != nil {
				err = msgp.WrapError(err)
				return
			}
		}
	}
	o = bts
	return
}

// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
func (z *allTierStats) Msgsize() (s int) {
	s = 1 + 3 + msgp.MapHeaderSize
	if z.Tiers != nil {
		for za0001, za0002 := range z.Tiers {
			_ = za0002

  }

  @CollectionFeature.Require(SERIALIZABLE)
  public void testInverseSerialization() {
    BiMapPair<K, V> pair = new BiMapPair<>(getMap());
    BiMapPair<K, V> copy = SerializableTester.reserialize(pair);
    assertEquals(pair.forward, copy.forward);
    assertEquals(pair.backward, copy.backward);
    assertSame(copy.backward, copy.forward.inverse());
    assertSame(copy.forward, copy.backward.inverse());
  }

		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		(*z) = rebalSaveOpts(zb0001)
	}
	o = bts
	return
}

// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
func (z rebalSaveOpts) Msgsize() (s int) {
	s = msgp.Uint8Size
	return
}

// DecodeMsg implements msgp.Decodable
func (z *rebalStatus) DecodeMsg(dc *msgp.Reader) (err error) {
	{
		var zb0001 uint8

 * (We have made some trivial local modifications (commented out
 * uncompilable code).)
 */

package com.google.common.util.concurrent;

import static com.google.common.testing.SerializableTester.reserialize;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

import com.google.common.annotations.GwtIncompatible;

    Collection<Integer> valuesCopy = SerializableTester.reserialize(multimap.values());
    assertEquals(HashMultiset.create(multimap.values()), HashMultiset.create(valuesCopy));
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testEmptySerialization() {
    Multimap<String, Integer> multimap = ImmutableSetMultimap.of();
    assertThat(SerializableTester.reserialize(multimap)).isSameInstanceAs(multimap);
  }

It also gives you a lot of **responsibility**. You have to make sure that the data you return is correct, in the correct format, that it can be serialized, etc.

## Using the `jsonable_encoder` in a `Response` { #using-the-jsonable-encoder-in-a-response }

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.