source: BufferedSource = socket.source().buffer(),
      sink: BufferedSink = socket.sink().buffer(),
    ) = apply {
      this.socket = socket
      this.connectionName =
        when {
          client -> "$okHttpName $peerName"
          else -> "MockWebServer $peerName"
        }
      this.source = source
      this.sink = sink
    }

    fun listener(listener: Listener) =
      apply {

You can create production applications with **FastAPI** right now (and you have probably been doing it for some time), you just have to make sure that you use a version that works correctly with the rest of your code.

## Pin your `fastapi` version

  private val isClient: Boolean,
  val sink: BufferedSink,
  val random: Random,
  private val perMessageDeflate: Boolean,
  private val noContextTakeover: Boolean,
  private val minimumDeflateSize: Long,
) : Closeable {
  /** This holds outbound data for compression and masking. */
  private val messageBuffer = Buffer()

  /** The [Buffer] of [sink]. Write to this and then flush/emit [sink]. */

/**
 * Utility methods and classes for I/O; for example input streams, output streams, readers, writers,
 * and files.
 *
 * <p>At the core of this package are the Source/Sink types: {@link ByteSource ByteSource}, {@link
 * CharSource CharSource}, {@link ByteSink ByteSink} and {@link CharSink CharSink}. They are
 * factories for I/O streams that provide many convenience methods that handle both opening and
 * closing streams for you.
 *

    Assertions.assertTrue(pin.matchesCertificate(certA1.certificate))
    Assertions.assertFalse(pin.matchesCertificate(certB1.certificate))
  }

  @Test
  fun testMatchesSha1() {
    val pin = CertificatePinner.Pin("example.com", certC1Sha1Pin)
    Assertions.assertTrue(pin.matchesCertificate(certC1.certificate))
    Assertions.assertFalse(pin.matchesCertificate(certB1.certificate))

    for (shift in (lengthByteCount - 1) * 8 downTo 0 step 8) {
      sink.writeByte((v shr shift).toInt())
    }
  }

  fun writeBitString(bitString: BitString) {
    val sink = sink()
    sink.writeByte(bitString.unusedBitsCount)
    sink.write(bitString.byteString)
  }

  fun writeOctetString(byteString: ByteString) {
    sink().write(byteString)
  }

  fun writeUtf8(value: String) {

Starlette (and **FastAPI**) are based on <a href="https://anyio.readthedocs.io/en/stable/" class="external-link" target="_blank">AnyIO</a>, which makes it compatible with both Python's standard library <a href="https://docs.python.org/3/library/asyncio-task.html" class="external-link" target="_blank">asyncio</a> and <a href="https://trio.readthedocs.io/en/stable/" class="external-link" target="_blank">Trio</a>.

   *     sink}
   */
  @CanIgnoreReturnValue
  public long copyTo(ByteSink sink) throws IOException {
    checkNotNull(sink);

    Closer closer = Closer.create();
    try {
      InputStream in = closer.register(openStream());
      OutputStream out = closer.register(sink.openStream());
      return ByteStreams.copy(in, out);
    } catch (Throwable e) {

/**
 * Utility methods and classes for I/O; for example input streams, output streams, readers, writers,
 * and files.
 *
 * <p>At the core of this package are the Source/Sink types: {@link ByteSource ByteSource}, {@link
 * CharSource CharSource}, {@link ByteSink ByteSink} and {@link CharSink CharSink}. They are
 * factories for I/O streams that provide many convenience methods that handle both opening and
 * closing streams for you.
 *

  }

  // The mask for the significand, according to the {@link
  // Double#doubleToRawLongBits(double)} spec.
  static final long SIGNIFICAND_MASK = 0x000fffffffffffffL;

  // The mask for the exponent, according to the {@link
  // Double#doubleToRawLongBits(double)} spec.
  static final long EXPONENT_MASK = 0x7ff0000000000000L;

  // The mask for the sign, according to the {@link
  // Double#doubleToRawLongBits(double)} spec.