header("Content-Encoding", "gzip")
      }

    val decompressed = zstdInterceptor.decompress(response)
    assertThat(decompressed.header("Content-Encoding")).isNull()

    val responseString = decompressed.body.string()
    assertThat(responseString).isEqualTo("hello gzip world")
  }

  @Test
  fun testNoDecompress() {
    val s = "hello not compressed world".encodeUtf8()

Interceptors can be chained. Suppose you have both a compressing interceptor and a checksumming interceptor: you'll need to decide whether data is compressed and then checksummed, or checksummed and then compressed. OkHttp uses lists to track interceptors, and interceptors are called in order.

![Interceptors Diagram](../assets/images/******@****.***)

### Application Interceptors

If there's no `gzip` in the header, it will not try to decompress the body.

That way, the same route class can handle gzip compressed or uncompressed requests.

{* ../../docs_src/custom_request_and_route/tutorial001_an_py310.py hl[9:16] *}

### Create a custom `GzipRoute` class { #create-a-custom-gziproute-class }

      disable: true # optionally turn-off snowball archive transfer
#      batch: 100 # upto this many objects per archive
#      inmemory: true # indicates if the archive must be staged locally or in-memory
#      compress: false # S2/Snappy compressed archive
#      smallerThan: 5MiB # create archive for all objects smaller than 5MiB
#      skipErrs: false # skips any source side read() errors

  # target where the objects must be replicated
  target:

    server.webSocket!!.send(message)
    taskFaker.runTasks()
    assertThat(client.clientSourceBufferSize())
      .isGreaterThan(message.length.toLong()) // Not compressed.
    assertThat(client.processNextFrame()).isTrue()
    client.listener.assertTextMessage(message)
  }

  @Test
  fun messagesCompressedWhenConfigured() {

@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableSet<E> extends ImmutableSet<E> {
  // We deliberately avoid caching the asList and hashCode here, to ensure that with
  // compressed oops, a SingletonImmutableSet packs all the way down to the optimal 16 bytes.

  final transient E element;

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableSet<E> extends ImmutableSet<E> {
  // We deliberately avoid caching the asList and hashCode here, to ensure that with
  // compressed oops, a SingletonImmutableSet packs all the way down to the optimal 16 bytes.

  final transient E element;

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

		return io.ErrUnexpectedEOF
	}
	ver := int(b[0])
	switch ver {
	case dataUsageCacheVerV1:
		return errors.New("cache version deprecated (will autoupdate)")
	case dataUsageCacheVerV2:
		// Zstd compressed.
		dec, err := zstd.NewReader(r, zstd.WithDecoderConcurrency(2))
		if err != nil {
			return err
		}
		defer dec.Close()

		dold := &dataUsageCacheV2{}

- Objects must be in CSV, JSON, or Parquet(*) format.
- UTF-8 is the only encoding type the Select API supports.
- GZIP or BZIP2 - CSV and JSON files can be compressed using GZIP, BZIP2, [ZSTD](https://facebook.github.io/zstd/), and streaming formats of [LZ4](https://lz4.github.io/lz4/), [S2](https://github.com/klauspost/compress/tree/master/s2#s2-compression) and [SNAPPY](http://google.github.io/snappy/).

import okio.GzipSink
import okio.buffer

internal class GzipRequestBody(
  val delegate: RequestBody,
) : RequestBody() {
  override fun contentType() = delegate.contentType()

  // We don't know the compressed length in advance!
  override fun contentLength() = -1L

  override fun writeTo(sink: BufferedSink) {
    GzipSink(sink).buffer().use(delegate::writeTo)
  }

  override fun isOneShot() = delegate.isOneShot()