reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *
   *  * If it is a control frame this will result in a single call to [FrameCallback].
   *  * If it is a message frame this will result in a single call to [FrameCallback.onReadMessage].
   *    If the message spans multiple frames, each interleaved control frame will result in a
   *    corresponding call to [FrameCallback].
   */

        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

import okio.ByteString.Companion.encodeUtf8

object Http2 {
  @JvmField
  val CONNECTION_PREFACE = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n".encodeUtf8()

  /** The initial max frame size, applied independently writing to, or reading from the peer. */
  const val INITIAL_MAX_FRAME_SIZE = 0x4000 // 16384

  const val TYPE_DATA = 0x0
  const val TYPE_HEADERS = 0x1
  const val TYPE_PRIORITY = 0x2
  const val TYPE_RST_STREAM = 0x3

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,

 * limitations under the License.
 */
package okhttp3.internal.http2

import java.io.IOException

/**
 * Thrown when an HTTP/2 connection is shutdown (either explicitly or if the peer has sent a GOAWAY
 * frame) and an attempt is made to use the connection.
 */

  /** Not an error!  */
  NO_ERROR(0),

  PROTOCOL_ERROR(1),

  INTERNAL_ERROR(2),

  FLOW_CONTROL_ERROR(3),

  SETTINGS_TIMEOUT(4),

  STREAM_CLOSED(5),

  FRAME_SIZE_ERROR(6),

  REFUSED_STREAM(7),

  CANCEL(8),

  COMPRESSION_ERROR(9),

  CONNECT_ERROR(0xa),

  ENHANCE_YOUR_CALM(0xb),

  INADEQUATE_SECURITY(0xc),

  HTTP_1_1_REQUIRED(0xd),
  ;

   * structures.
   *
   * We make such subtle calls in [okhttp3.internal.ws.MessageInflater] because we try to read a
   * compressed stream that is terminated in a web socket frame even though the DEFLATE stream is
   * not terminated.
   *
   * Use this method to create a degenerate Okio Buffer where each byte is in a separate segment of
   * the internal list.
   */
  @JvmStatic

    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)

    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.

 * https, etc.) of the URL, not the protocol (http/1.1, spdy/3.1, etc.). OkHttp uses the word
 * *protocol* to identify how HTTP messages are framed.
 *
 * [ietf_alpn]: http://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg
 */
enum class Protocol(private val protocol: String) {
  /**