* `permessage-deflate` and four parameters, `client_max_window_bits`, `client_no_context_takeover`,
 * `server_max_window_bits`, and `server_no_context_takeover`.
 *
 * Typically this will look like one of the following:
 *
 * ```
 * Sec-WebSocket-Extensions: permessage-deflate
 * Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits="15"

    assertThat(parse("permessage-deflate; client_max_window_bits=8")).isEqualTo(
      WebSocketExtensions(perMessageDeflate = true, clientMaxWindowBits = 8),
    )
    assertThat(parse("permessage-deflate; client_max_window_bits=\"8\"")).isEqualTo(
      WebSocketExtensions(perMessageDeflate = true, clientMaxWindowBits = 8),
    )
    assertThat(parse("permessage-deflate; client_max_window_bits=15")).isEqualTo(

  private fun WebSocketExtensions.isValid(): Boolean {
    // If the server returned parameters we don't understand, fail the web socket.
    if (unknownValues) return false

    // If the server returned a value for client_max_window_bits, fail the web socket.
    if (clientMaxWindowBits != null) return false

    // If the server returned an illegal server_max_window_bits, fail the web socket.

  }

  @Test
  @Throws(Exception::class)
  fun clientMaxWindowBitsIncluded() {
    extensionNegotiationFailure("permessage-deflate; client_max_window_bits=15")
  }

  @Test
  @Throws(Exception::class)
  fun serverMaxWindowBitsTooLow() {
    extensionNegotiationFailure("permessage-deflate; server_max_window_bits=7")
  }

  @Test