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.

pkg runtime, func CallersFrames([]uintptr) *Frames
pkg runtime, func KeepAlive(interface{})
pkg runtime, func SetCgoTraceback(int, unsafe.Pointer, unsafe.Pointer, unsafe.Pointer)
pkg runtime, method (*Frames) Next() (Frame, bool)
pkg runtime, type Frame struct
pkg runtime, type Frame struct, Entry uintptr
pkg runtime, type Frame struct, File string
pkg runtime, type Frame struct, Func *Func

    close(ErrorCode.PROTOCOL_ERROR, ErrorCode.PROTOCOL_ERROR, e)
  }

  /**
   * Sends any initial frames and starts reading frames from the remote peer. This should be called
   * after [Builder.build] for all new connections.
   *
   * @param sendConnectionPreface true to send connection preface frames. This should always be true
   *     except for in tests that don't check for a connection preface.

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,

```
$ 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

      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.")
    }
  }

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.

 *  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.

 * limitations under the License.
 */
package mockwebserver3

import okhttp3.ExperimentalOkHttpApi
import okio.BufferedSink
import okio.BufferedSource

/**
 * A bidirectional sequence of data frames exchanged between client and server.
 */
@ExperimentalOkHttpApi
interface Stream {
  val requestBody: BufferedSource
  val responseBody: BufferedSink

  /**

    while (buffer.size != 1024L) source.read(buffer, 1024)
    stream1.close(ErrorCode.CANCEL, null)
    val frame1 = peer.takeFrame()
    assertThat(frame1.type).isEqualTo(Http2.TYPE_HEADERS)
    val frame2 = peer.takeFrame()
    assertThat(frame2.type).isEqualTo(Http2.TYPE_RST_STREAM)
    val frame3 = peer.takeFrame()
    assertThat(frame3.type).isEqualTo(Http2.TYPE_RST_STREAM)
    assertThat(connection.readBytes.acknowledged).isEqualTo(0L)