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.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
[2020-01-01 00:00:00] >> 0x00000000     4 WINDOW_UPDATE

   questions. Those who are asked should be responsive and helpful.

 * **Step down considerately**: Members of every project come and go. When somebody leaves or
   disengages from the project, they should make it known and take the proper steps to ensure that
   others can pick up where they left off.

  integrity sha512-XnAIvQ8eM+kC6aULx6wuQiwVsnzsi9d3WxzV3FpWTGA19F621kwdbsAcFKXgKUHZWsy+mY6iL1sHTxWEFCytDA==
  dependencies:
    balanced-match "^1.0.0"

braces@^3.0.2, braces@~3.0.2:
  version "3.0.2"
  resolved "https://registry.yarnpkg.com/braces/-/braces-3.0.2.tgz#3454e1a462ee8d599e236df336cd9ea4f8afe107"
  integrity sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==
  dependencies:

 *  New: Support the `immutable` cache-control directive.
 *  Fix: Don't crash when an HTTP/2 call is redirected while the connection is
    being shut down.
 *  Fix: Don't drop headers of healthy streams that raced with `GOAWAY` frames.
    This bug would cause HTTP/2 streams to occasional hang when the connection
    was shutting down.
 *  Fix: Honor `OkHttpClient.retryOnConnectionFailure()` when the response is a

   * 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() {
        override fun dispatch(request: RecordedRequest): MockResponse {

   *
   *  * A regular host name, like `android.com`.
   *
   *  * An IPv4 address, like `127.0.0.1`.
   *
   *  * An IPv6 address, like `::1`. Note that there are no square braces.
   *
   *  * An encoded IDN, like `xn--n3h.net`.
   *
   * | URL                   | `host()`        |
   * | :-------------------- | :-------------- |
   * | `http://android.com/` | `"android.com"` |

    val call2 = client.newCall(Request(server.url("/")))
    val response2 = call2.execute()
    assertThat(response2.body.string()).isEqualTo("abc")
  }

  /** Wait for the client to receive `dataLength` DATA frames.  */
  private fun waitForDataFrames(dataLength: Int) {
    val expectedFrameCount = dataLength / 16384
    var dataFrameCount = 0
    while (dataFrameCount < expectedFrameCount) {
      val log = testLogHandler.take()

 *  * [onHeaders] (unless canceled)
 *  * [onData] (optional sequence of data frames)
 *
 * As a stream ID is scoped to a single HTTP/2 connection, implementations which target multiple
 * connections should expect repetition of stream IDs.
 *
 * Return true to request cancellation of a pushed stream.  Note that this does not guarantee
 * future frames won't arrive on the stream ID.
 */
interface PushObserver {
  /**

  private val pongQueue = ArrayDeque<ByteString>()

  /** Outgoing messages and close frames in the order they should be written. */
  private val messageAndCloseQueue = ArrayDeque<Any>()

  /** The total size in bytes of enqueued but not yet transmitted messages. */
  private var queueSize = 0L

  /** True if we've enqueued a close frame. No further message frames will be enqueued. */
  private var enqueuedClose = false