*  Fix: MockWebServer explicitly closes sockets. (On some Android releases,
    closing the input stream and output stream of a socket is not sufficient.
 *  Fix: Buffer outgoing HTTP/2 frames to limit how many outgoing frames are
    created.
 *  Fix: Avoid crashing when cache writing fails due to a full disk.
 *  Fix: Improve caching of private responses.
 *  Fix: Update cache-by-default response codes.

    writeMedium(frame, (headerBlock.size / 2).toInt() + paddingLength + 1)
    frame.writeByte(Http2.TYPE_HEADERS)
    frame.writeByte(FLAG_PADDED)
    frame.writeInt(expectedStreamId and 0x7fffffff)
    frame.writeByte(paddingLength)
    frame.write(headerBlock, headerBlock.size / 2)
    frame.write(padding)

    // Write the continuation frame, specifying no more frames are expected.

So we have a dedicated thread for every socket that just reads frames and dispatches them.

The reader thread must never run application-layer code. Otherwise one slow stream can hold up the entire connection.

      assertThat(expected.message)
        .isEqualTo("Client-sent frames must be masked.")
    }
  }

  @Test fun serverSentFramesMustNotBeMasked() {
    data.write("8180".decodeHex())
    assertFailsWith<ProtocolException> {
      clientReader.processNextFrame()
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("Server-sent frames must not be masked.")
    }
  }

```
$ adb shell setprop log.tag.okhttp.Http2 DEBUG
$ adb shell setprop log.tag.okhttp.TaskRunner DEBUG
$ adb logcat '*:E' 'okhttp.Http2:D' 'okhttp.TaskRunner:D'
```

### HTTP/2 Frame Logging

This logs inbound (`<<`) and outbound (`>>`) frames for HTTP/2 connections.

```
[2020-01-01 00:00:00] >> CONNECTION 505249202a20485454502f322e300d0a0d0a534d0d0a0d0a
[2020-01-01 00:00:00] >> 0x00000000     6 SETTINGS

class WindowCounter(
  val streamId: Int,
) {
  /** The total number of bytes consumed. */
  var total: Long = 0L
    private set

  /** The total number of bytes acknowledged by outgoing `WINDOW_UPDATE` frames. */
  var acknowledged: Long = 0L
    private set

  val unacknowledged: Long
    @Synchronized get() = total - acknowledged

  @Synchronized
  fun update(
    total: Long = 0,
    acknowledged: Long = 0,

    List<Integer> completeLengthChecks;
    int baseStackDepth;
    ExecutorService service = newFixedThreadPool(5);
    try {
      // Avoid counting frames from the executor itself, or the ExecutionSequencer
      baseStackDepth =
          serializer
              .submit(
                  new Callable<Integer>() {
                    @Override

import okhttp3.internal.http2.Header.Companion.TARGET_SCHEME_UTF8
import okhttp3.internal.immutableListOf
import okio.Sink
import okio.Socket
import okio.Source

/** Encode requests and responses using HTTP/2 frames. */
class Http2ExchangeCodec(
  client: OkHttpClient,
  override val carrier: Carrier,
  private val chain: RealInterceptorChain,
  private val http2Connection: Http2Connection,
) : ExchangeCodec {

      .isEqualTo("<< 0x00000003   226 DATA          END_STREAM")
    assertThat(frameLog(false, 0, 8, TYPE_GOAWAY, FLAG_NONE))
      .isEqualTo(">> 0x00000000     8 GOAWAY        ")
  }

  /** Window update frames have special formatting.  */
  @Test
  fun windowUpdateFrames() {
    assertThat(frameLogWindowUpdate(false, 0, 4, Int.MAX_VALUE.toLong()))
      .isEqualTo(">> 0x00000000     4 WINDOW_UPDATE 2147483647")

    assertThat(webSocket.close(1000, null)).isFalse()
  }

  /**
   * There's no read timeout when reading the first byte of a new frame. But as soon as we start
   * reading a frame we enable the read timeout. In this test we have the server returning the first
   * byte of a frame but no more frames.
   */
  @Test
  fun readTimeoutAppliesWithinFrames() {
    webServer.dispatcher =
      object : Dispatcher() {