}

    val lengthByteCount = (lengthBitCount + 7) / 8
    for (shift in (lengthByteCount - 1) * 8 downTo 0 step 8) {
      sink.writeByte((v shr shift).toInt())
    }
  }

  fun writeBitString(bitString: BitString) {
    val sink = sink()
    sink.writeByte(bitString.unusedBitsCount)
    sink.write(bitString.byteString)
  }

  fun writeOctetString(byteString: ByteString) {

  @Test fun `encode primitive bit string`() {
    val buffer = Buffer()
    val derWriter = DerWriter(buffer)

    derWriter.write("test", tagClass = DerHeader.TAG_CLASS_UNIVERSAL, tag = 3L) {
      derWriter.writeBitString(BitString("0A3B5F291CD0".decodeHex(), 4))
    }

    assertThat(buffer.readByteString()).isEqualTo("0307040A3B5F291CD0".decodeHex())
  }

  @Test fun `decode primitive string`() {
    val buffer =