// The Header.Size determines how many bytes can be written for the next file.
// If the current file is not fully written, then this returns an error.
// This implicitly flushes any padding necessary before writing the header.
func (tw *Writer) WriteHeader(hdr *Header) error {
	if err := tw.Flush(); err != nil {
		return err
	}
	tw.hdr = *hdr // Shallow copy of Header

		}
	}
}

var fromContentMD5Tests = []struct {
	Header     http.Header
	ETag       ETag
	ShouldFail bool
}{
	{Header: http.Header{}, ETag: nil}, // 0
	{Header: http.Header{"Content-Md5": []string{"1B2M2Y8AsgTpgAmY7PhCfg=="}}, ETag: must("d41d8cd98f00b204e9800998ecf8427e")},                             // 1

				w.Header().Set(xhttp.AmzServerSideEncryptionKmsContext, kmsCtx)
			}
		case crypto.SSEC:
			w.Header().Set(xhttp.AmzServerSideEncryptionCustomerAlgorithm, r.Header.Get(xhttp.AmzServerSideEncryptionCustomerAlgorithm))
			w.Header().Set(xhttp.AmzServerSideEncryptionCustomerKeyMD5, r.Header.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5))
		}
		objInfo.ETag = getDecryptedETag(r.Header, objInfo, false)
	}

Y como la `Response` puede ser usada frecuentemente para configurar headers y cookies, **FastAPI** también la provee en `fastapi.Response`.

///

## Headers Personalizados

Ten en cuenta que se pueden añadir headers propietarios personalizados <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">usando el prefijo 'X-'</a>.

package cmd

// Code generated by github.com/tinylib/msgp DO NOT EDIT.

import (
	"github.com/tinylib/msgp/msgp"
)

// DecodeMsg implements msgp.Decodable
func (z *BatchJobKV) DecodeMsg(dc *msgp.Reader) (err error) {
	var field []byte
	_ = field
	var zb0001 uint32
	zb0001, err = dc.ReadMapHeader()
	if err != nil {
		err = msgp.WrapError(err)
		return
	}
	for zb0001 > 0 {
		zb0001--
		field, err = dc.ReadMapKeyPtr()

* Performance test framework and basic tests for the IPAM controller, to simulate behavior of the four supported modes under lightly loaded and loaded conditions, where load is defined as the number of operations to perform as against the configured kubernetes. ([#61143](https://github.com/kubernetes/kubernetes/pull/61143), [@satyasm](https://github.com/satyasm))

 */
class Http2Reader(
  /** Creates a frame reader with max header table size of 4096. */
  private val source: BufferedSource,
  private val client: Boolean,
) : Closeable {
  private val continuation: ContinuationSource = ContinuationSource(this.source)
  private val hpackReader: Hpack.Reader =
    Hpack.Reader(
      source = continuation,
      headerTableSizeSetting = 4096,
    )

    }

    /**
     * Checks if `expected` and `observed` are equal when viewed as a set and headers are
     * deduped.
     *
     * TODO: See if duped headers should be preserved on decode and verify.
     */
    private fun assertSetEquals(
      message: String,
      expected: List<Header>,
      observed: List<Header>,
    ) {
      assertThat(LinkedHashSet(observed), message)
        .isEqualTo(LinkedHashSet(expected))

        return api_key


class APIKeyHeader(APIKeyBase):
    """
    API key authentication using a header.

    This defines the name of the header that should be provided in the request with
    the API key and integrates that into the OpenAPI documentation. It extracts
    the key value sent in the header automatically and provides it as the dependency
    result. But it doesn't define how to send that key to the client.

			}
			type version struct {
				Idx      int
				Header   json.RawMessage
				Metadata json.RawMessage
			}
			versions := make([]version, nVers)
			e = decodeVersions(v, nVers, func(idx int, hdr, meta []byte) error {
				var header xlMetaV2VersionHeaderV2
				if _, e := header.UnmarshalMsg(hdr); e != nil {
					return e
				}
				b, e := header.MarshalJSON()
				if e != nil {
					return e
				}