val dataSize = messageBuffer.size
    sinkBuffer.writeByte(b0)

    var b1 = 0
    if (isClient) {
      b1 = b1 or B1_FLAG_MASK
    }
    when {
      dataSize <= PAYLOAD_BYTE_MAX -> {
        b1 = b1 or dataSize.toInt()
        sinkBuffer.writeByte(b1)
      }
      dataSize <= PAYLOAD_SHORT_MAX -> {
        b1 = b1 or PAYLOAD_SHORT
        sinkBuffer.writeByte(b1)
        sinkBuffer.writeShort(dataSize.toInt())

        sink.writeUtf8(url.toString()).writeByte('\n'.code)
        sink.writeUtf8(requestMethod).writeByte('\n'.code)
        sink.writeDecimalLong(varyHeaders.size.toLong()).writeByte('\n'.code)
        for (i in 0 until varyHeaders.size) {
          sink
            .writeUtf8(varyHeaders.name(i))
            .writeUtf8(": ")
            .writeUtf8(varyHeaders.value(i))
            .writeByte('\n'.code)
        }

      val byte0 = tagClass or constructedBit or tag.toInt()
      sink.writeByte(byte0)
    } else {
      val byte0 = tagClass or constructedBit or 0b0001_1111
      sink.writeByte(byte0)
      writeVariableLengthLong(tag)
    }

    // Write the length. This takes 1 byte if length is less than 128.
    val length = content.size
    if (length < 128) {
      sink.writeByte(length.toInt())
    } else {

      writeUtf8(MAGIC).writeByte('\n'.code)
      writeUtf8(VERSION_1).writeByte('\n'.code)
      writeDecimalLong(appVersion.toLong()).writeByte('\n'.code)
      writeDecimalLong(valueCount.toLong()).writeByte('\n'.code)
      writeByte('\n'.code)

      for (entry in lruEntries.values) {
        if (entry.currentEditor != null) {
          writeUtf8(DIRTY).writeByte(' '.code)
          writeUtf8(entry.key)

      }

      while (!encodedCharBuffer.exhausted()) {
        val b = encodedCharBuffer.readByte().toInt() and 0xff
        writeByte('%'.code)
        writeByte(HEX_DIGITS[b shr 4 and 0xf].code)
        writeByte(HEX_DIGITS[b and 0xf].code)
      }
    } else {
      // This character doesn't need encoding. Just copy it over.
      writeUtf8CodePoint(codePoint)
    }

          rangesBuffer.writeByte(range.b1)
          rangesBuffer.writeByte('-'.code)
          rangesBuffer.writeByte('-'.code)
        }
        is MappedRange.Inline1 -> {
          rangesBuffer.writeByte(range.b1)
          rangesBuffer.writeByte(range.b2)
          rangesBuffer.writeByte('-'.code)
        }
        is MappedRange.Inline2 -> {
          rangesBuffer.writeByte(range.b1)
          rangesBuffer.writeByte(range.b2)

    val expected =
      Buffer()
        .writeByte(0x40) // Literal header, new name.
        .writeByte(0x82) // String literal is Huffman encoded (len = 2).
        .writeByte(0x94) // 'foo' Huffman encoded.
        .writeByte(0xE7)
        .writeByte(3) // String literal not Huffman encoded (len = 3).
        .writeByte('b'.code)
        .writeByte('a'.code)
        .writeByte('r'.code)
        .readByteString()

    assertThat(Buffer().writeUtf8("white\t space").isProbablyUtf8()).isTrue()
    assertThat(Buffer().writeByte(0x80).isProbablyUtf8()).isTrue()
    assertThat(Buffer().writeByte(0x00).isProbablyUtf8()).isFalse()
    assertThat(Buffer().writeByte(0xc0).isProbablyUtf8()).isFalse()
  }

    val headerBytes = literalHeaders(sentHeaders)
    writeMedium(frame, (headerBytes.size + 5).toInt())
    frame.writeByte(Http2.TYPE_HEADERS)
    frame.writeByte(FLAG_END_HEADERS or FLAG_PRIORITY)
    frame.writeInt(expectedStreamId and 0x7fffffff)
    frame.writeInt(0) // Independent stream.
    frame.writeByte(255) // Heaviest weight, zero-indexed.
    frame.writeAll(headerBytes)
    reader.nextFrame(
      requireSettings = false,

        // Mapped inline to the sequence: [b2].
        sink.writeByte(ranges[rangesIndex + 2].code)
      }
      123 -> {
        // Mapped inline to the sequence: [b2a].
        sink.writeByte(ranges[rangesIndex + 2].code or 0x80)
      }
      124 -> {
        // Mapped inline to the sequence: [b2, b3].
        sink.writeByte(ranges[rangesIndex + 2].code)
        sink.writeByte(ranges[rangesIndex + 3].code)
      }
      125 -> {