responseDequeuedLatches[responseIndex].countDown()
      requestCanceledLatches[responseIndex].await()
      responseIndex++
      return response
    }
  }

  /** Make a call and canceling it as soon as it's accepted by the server.  */
  private fun callAndCancel(
    expectedSequenceNumber: Int,
    responseDequeuedLatch: CountDownLatch?,
    requestCanceledLatch: CountDownLatch?,
  ) {

    assertArrayEquals("fghi".toByteArray(), data2.data)
  }

  /**
   * Confirm that we account for discarded data frames. It's possible that data frames are in-flight
   * just prior to us canceling a stream.
   */
  @Test fun discardedDataFramesAreCounted() {
    // Write the mocking script.
    peer.sendFrame().settings(Settings())
    peer.acceptFrame() // ACK
    peer.acceptFrame() // SYN_STREAM 3