* [Byte Order Mark (BOM)](https://en.wikipedia.org/wiki/Byte_order_mark), it is consumed and
   * used to determine the charset of the response bytes.
   *
   * Otherwise if the response has a `Content-Type` header that specifies a charset, that is used
   * to determine the charset of the response bytes.
   *
   * Otherwise the response bytes are decoded as UTF-8.
   */
  fun charStream(): Reader =

			req.Header.Set("X-Amz-Copy-Source-If-Modified-Since", testCase.copyModifiedHeader)
		}
		if testCase.copyUnmodifiedHeader != "" {
			req.Header.Set("X-Amz-Copy-Source-If-Unmodified-Since", testCase.copyUnmodifiedHeader)
		}
		// Add custom metadata.
		for k, v := range testCase.metadata {
			req.Header.Set(k, v)
		}
		if testCase.metadataReplace {

  * As part of preparation in 1.2 for adding support for protocol buffers (and the
direct YAML support in the API available today), the Content-Type and Accept
headers are now properly handled as per the HTTP spec.  As a consequence, if
you had a client that was sending an invalid Content-Type or Accept header to
the API, in 1.2 you will either receive a 415 or 406 error.
The only client
this is known to affect is curl when you use -d with JSON but don't set a

* 然后你可以在返回 `response` 前进一步修改它.

```Python hl_lines="8-9  11  14"
{!../../docs_src/middleware/tutorial001.py!}
```

/// tip

请记住可以 <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">用'X-' 前缀</a>添加专有自定义请求头.

            off = in.read(buf, 0, 1024);
        } else {
            off = in.readDirect(buf, 0, buf.length);
        }

        if (buf[0] != 5 && buf[1] != 0)
            throw new IOException("Unexpected DCERPC PDU header");

        flags = buf[3] & 0xFF;
        // next read is start of new frag
        isStart = (flags & DCERPC_LAST_FRAG) == DCERPC_LAST_FRAG;

        length = Encdec.dec_uint16le(buf, 8);

        val request = HttpRequest.newBuilder()
            .uri(URI(uri))
            .apply {
                if (githubToken.isPresent) {
                    header("Authorization", "token ${githubToken.get()}")
                }
            }
            .build()
        val response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString())

                log.println( "SecurityException: jcifs.smb1 will ignore System properties" );
        }
    }

    public static void store( OutputStream out, String header ) throws IOException {
        prp.store( out, header );
    }

    /**
     * List the properties in the <code>Code</code>.
     */

    public static void list( PrintStream out ) throws IOException {
        prp.list( out );

 *
 * @author Kurt Alfred Kluever
 */
public class HttpHeadersTest extends TestCase {

  public void testConstantNameMatchesString() throws Exception {
    // Special case some of the weird HTTP Header names...
    ImmutableBiMap<String, String> specialCases =
        ImmutableBiMap.<String, String>builder()
            .put("CDN_LOOP", "CDN-Loop")
            .put("ETAG", "ETag")
            .put("SOURCE_MAP", "SourceMap")

 *
 * @author Kurt Alfred Kluever
 */
public class HttpHeadersTest extends TestCase {

  public void testConstantNameMatchesString() throws Exception {
    // Special case some of the weird HTTP Header names...
    ImmutableBiMap<String, String> specialCases =
        ImmutableBiMap.<String, String>builder()
            .put("CDN_LOOP", "CDN-Loop")
            .put("ETAG", "ETag")
            .put("SOURCE_MAP", "SourceMap")

			decSize, err := sio.DecryptedSize(uint64(n))
			if err == nil {
				actualSize = int64(decSize)
			}
		default:
			actualSize = n
		}
	}
	if fi.Checksum == nil {
		// Trailing headers checksums should now be filled.
		fi.Checksum = opts.WantChecksum.AppendTo(nil, nil)
		if opts.EncryptFn != nil {
			fi.Checksum = opts.EncryptFn("object-checksum", fi.Checksum)
		}
	}