/** 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

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

    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)

import okio.ByteString
import okio.Source
import okio.Timeout

/**
 * Reads HTTP/2 transport frames.
 *
 * This implementation assumes we do not send an increased [frame][Settings.getMaxFrameSize] to the
 * peer. Hence, we expect all frames to have a max length of [Http2.INITIAL_MAX_FRAME_SIZE].
 */
class Http2Reader(
  /** Creates a frame reader with max header table size of 4096. */
  private val source: BufferedSource,

        if (closed) return
        outFinished = errorCode == null
      }
      if (!sink.finished) {
        // We have 0 or more frames of data, and 0 or more frames of trailers. We need to send at
        // least one frame with the END_STREAM flag set. That must be the last frame, and the
        // trailers must be sent after all of the data.
        val hasData = sendBuffer.size > 0L
        val hasTrailers = trailers != null

      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.")
    }
  }

used to refer to frame-local variables and the arguments being
prepared for function calls.
It points to the highest address within the local stack frame, so references should use negative offsets
in the range [−framesize, 0):
<code>x-8(SP)</code>, <code>y-4(SP)</code>, and so on.
</p>

<p>
On architectures with a hardware register named <code>SP</code>,
the name prefix distinguishes

```
$ 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

    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.

  /**
   * HTTP/2 only. Send a push promise header block.
   *
   * A push promise contains all the headers that pertain to a server-initiated request, and a
   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as
   * a part of the response to `streamId`. The `promisedStreamId` has a priority of one greater than
   * `streamId`.
   *
   * @param streamId client-initiated stream ID.  Must be an odd number.