val decoded = Punycode.decode(bufferA.readUtf8()) ?: return null

  // 4.1 Validate.

  // Must be NFC.
  if (decoded != normalizeNfc(decoded)) return null

  // TODO: Must not begin with a combining mark.
  // TODO: Each character must be 'valid' or 'deviation'. Not mapped.
  // TODO: CheckJoiners from IDNA 2008
  // TODO: CheckBidi from IDNA 2008, RFC 5893, Section 2.

  return Punycode.encode(decoded)

    // zero-width joiner
    assertThat(parse("http://h/\u200d").encodedPath).isEqualTo("/%E2%80%8D")
    // left-to-right mark
    assertThat(parse("http://h/\u200e").encodedPath).isEqualTo("/%E2%80%8E")
    // right-to-left mark
    assertThat(parse("http://h/\u200f").encodedPath).isEqualTo("/%E2%80%8F")
    // line separator
    assertThat(parse("http://h/\u2028").encodedPath).isEqualTo("/%E2%80%A8")

    server.enqueue(builder.build())
    val inputStream = getResponse(newRequest("/")).body.byteStream()
    assertThat(inputStream.markSupported(), "This implementation claims to support mark().")
      .isFalse()
    inputStream.mark(5)
    assertThat(readAscii(inputStream, 5)).isEqualTo("ABCDE")
    assertFailsWith<IOException> {
      inputStream.reset()
    }

  @Throws(IOException::class)
  fun byteString() = commonByteString()

  /**
   * Returns the response as a character stream.
   *
   * If the response starts with a
   * [Byte Order Mark (BOM)](https://en.wikipedia.org/wiki/Byte_order_mark), it is consumed and
   * used to determine the charset of the response bytes.
   *
   * Otherwise if the response has a `Content-Type` header that specifies a charset, that is used

 *  New: Make `ResponseBody.string()` and `ResponseBody.charStream()` BOM-aware. If your HTTP
    response body begins with a [byte order mark][bom] it will be consumed and used to select a
    charset for the remaining bytes. Most applications should not need a byte order mark.

 *  New: Upgrade to Okio 1.11.0.

     ```xml
     <dependency>
       <groupId>com.squareup.okio</groupId>

   00A0; NO-BREAK SPACE
   1680; OGHAM SPACE MARK
   2000; EN QUAD
   2001; EM QUAD
   2002; EN SPACE
   2003; EM SPACE
   2004; THREE-PER-EM SPACE
   2005; FOUR-PER-EM SPACE
   2006; SIX-PER-EM SPACE
   2007; FIGURE SPACE
   2008; PUNCTUATION SPACE
   2009; THIN SPACE
   200A; HAIR SPACE
   200B; ZERO WIDTH SPACE
   202F; NARROW NO-BREAK SPACE
   205F; MEDIUM MATHEMATICAL SPACE

    proxySelector.proxies.add(proxyA)
    proxySelector.proxies.add(proxyB)
    var routeSelector = newRouteSelector(address)
    dns[PROXY_A_HOST] = dns.allocate(1)
    dns[PROXY_B_HOST] = dns.allocate(1)

    // Mark the ProxyA route as failed.
    val selection = routeSelector.next()
    dns.assertRequests(PROXY_A_HOST)
    val route = selection.next()
    assertRoute(route, address, proxyA, dns.lookup(PROXY_A_HOST, 0), PROXY_A_PORT)

   0340; COMBINING GRAVE TONE MARK
   0341; COMBINING ACUTE TONE MARK
   200E; LEFT-TO-RIGHT MARK
   200F; RIGHT-TO-LEFT MARK
   202A; LEFT-TO-RIGHT EMBEDDING
   202B; RIGHT-TO-LEFT EMBEDDING
   202C; POP DIRECTIONAL FORMATTING
   202D; LEFT-TO-RIGHT OVERRIDE
   202E; RIGHT-TO-LEFT OVERRIDE
   206A; INHIBIT SYMMETRIC SWAPPING
   206B; ACTIVATE SYMMETRIC SWAPPING
   206C; INHIBIT ARABIC FORM SHAPING
   206D; ACTIVATE ARABIC FORM SHAPING

309B          ; disallowed_STD3_mapped ; 0020 3099     # 1.1  KATAKANA-HIRAGANA VOICED SOUND MARK
309C          ; disallowed_STD3_mapped ; 0020 309A     # 1.1  KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK
309D..309E    ; valid                                  # 1.1  HIRAGANA ITERATION MARK..HIRAGANA VOICED ITERATION MARK

   0080-009F; [CONTROL CHARACTERS]
   06DD; ARABIC END OF AYAH
   070F; SYRIAC ABBREVIATION MARK
   180E; MONGOLIAN VOWEL SEPARATOR
   200C; ZERO WIDTH NON-JOINER
   200D; ZERO WIDTH JOINER
   2028; LINE SEPARATOR
   2029; PARAGRAPH SEPARATOR
   2060; WORD JOINER
   2061; FUNCTION APPLICATION
   2062; INVISIBLE TIMES
   2063; INVISIBLE SEPARATOR
   206A-206F; [CONTROL CHARACTERS]
   FEFF; ZERO WIDTH NO-BREAK SPACE