assertFailsWith<ProtocolException> {
      clientReader.processNextFrame()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Unexpected rsv1 flag")
    }
  }

  @Test fun reservedFlag1IsUnsupportedForControlFrames() {
    data.write("ca00".decodeHex()) // Empty pong, flag 1 set.
    assertFailsWith<ProtocolException> {
      clientReaderWithCompression.processNextFrame()
    }.also { expected ->