return new RequestBody() {
      @Override public MediaType contentType() {
        return body.contentType();
      }

      @Override public long contentLength() {
        return -1; // We don't know the compressed length in advance!
      }

      @Override public void writeTo(BufferedSink sink) throws IOException {
        BufferedSink gzipSink = Okio.buffer(new GzipSink(sink));
        body.writeTo(gzipSink);

```java
HandshakeCertificates serverHandshakeCertificates = new HandshakeCertificates.Builder()
    .heldCertificate(serverCertificate, intermediateCertificate.certificate())
    .build();
```

The client only needs to know the trusted root certificate. It checks the server's certificate by
validating the signatures within the chain.

```java
HandshakeCertificates clientCertificates = new HandshakeCertificates.Builder()

## Mix `Path`, `Query` and body parameters

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

//// tab | Python 3.10+

```Python hl_lines="18-20"
{!> ../../docs_src/body_multiple_params/tutorial001_an_py310.py!}

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded` when it doesn't include files.

But when the form includes files, it is encoded as `multipart/form-data`. If you use `File`, **FastAPI** will know it has to get the files from the correct part of the body.

  /**
   * Returns the comparator that orders the columns. With natural ordering, {@link
   * Ordering#natural()} is returned.
   *
   * @deprecated Store the {@link Comparator} alongside the {@link Table}. Or, if you know that the
   *     {@link Table} contains at least one value, you can retrieve the {@link Comparator} with:
   *     {@code ((SortedMap<C, V>) table.rowMap().values().iterator().next()).comparator();}.
   */
  @Deprecated

    try {
      /*
       * Converter.apply has a non-nullable parameter type but doesn't throw for null arguments. For
       * more information, see the comments in that class.
       *
       * We already know that that's how it behaves, and subclasses of Converter can't change that
       * behavior. So there's no sense in making all subclass authors exclude the method from any
       * NullPointerTester tests that they have.
       */

                    } else {
                        encodedBuf.append(converted);
                    }
                } catch (final UnsupportedEncodingException e) {
                    // NOP
                }
            }
        }

        final String id = encodedBuf.toString();
        return MessageDigestUtil.digest(ComponentUtil.getFessConfig().getIndexIdDigestAlgorithm(), id);
    }

    }

    public void test_getText_null() {
        try {
            jodExtractor.getText(null, null);
            fail();
        } catch (CrawlerSystemException e) {
            // NOP
        }
    }

 *
 * Unfortunately Java's networking APIs don't offer a good health check, so we go on our own by
 * attempting to read with a short timeout. If the fails immediately we know the socket is
 * unhealthy.
 *
 * @param source the source used to read bytes from the socket.
 */
internal fun Socket.isHealthy(source: BufferedSource): Boolean {
  return try {
    val readTimeout = soTimeout

    try {
      /*
       * Converter.apply has a non-nullable parameter type but doesn't throw for null arguments. For
       * more information, see the comments in that class.
       *
       * We already know that that's how it behaves, and subclasses of Converter can't change that
       * behavior. So there's no sense in making all subclass authors exclude the method from any
       * NullPointerTester tests that they have.
       */