object : ResponseBody() {
        override fun contentType(): MediaType? = null

        override fun contentLength(): Long = 5

        override fun source(): BufferedSource {
          val source = Buffer().writeUtf8("hello")
          return object : ForwardingSource(source) {
            @Throws(IOException::class)
            override fun close() {
              closed.set(true)
              super.close()
            }

  ) {
    check(state == STATE_IDLE) { "state: $state" }
    socket.sink.writeUtf8(requestLine).writeUtf8("\r\n")
    for (i in 0 until headers.size) {
      socket.sink
        .writeUtf8(headers.name(i))
        .writeUtf8(": ")
        .writeUtf8(headers.value(i))
        .writeUtf8("\r\n")
    }
    socket.sink.writeUtf8("\r\n")
    state = STATE_OPEN_REQUEST_BODY
  }

        entry.readable = true
        writeUtf8(CLEAN).writeByte(' '.code)
        writeUtf8(entry.key)
        entry.writeLengths(this)
        writeByte('\n'.code)
        if (success) {
          entry.sequenceNumber = nextSequenceNumber++
        }
      } else {
        lruEntries.remove(entry.key)
        writeUtf8(REMOVE).writeByte(' '.code)
        writeUtf8(entry.key)
        writeByte('\n'.code)
      }

      |mnop
      |
      |--simple boundary--
      """.trimMargin()
        .replace("\n", "\r\n")

    val parts =
      MultipartReader(
        boundary = "simple boundary",
        source = Buffer().writeUtf8(multipart),
      )
    assertThat(parts.boundary).isEqualTo("simple boundary")

    val partAbc = parts.nextPart()!!
    assertThat(partAbc.headers).isEqualTo(
      headersOf(
        "Content-Type",

    bytesIn.writeUtf8("custom-foo")
    bytesIn.writeByte(0x0d) // Literal value (len = 13)
    bytesIn.writeUtf8("custom-header")
    bytesIn.writeByte(0x40) // Literal indexed
    bytesIn.writeByte(0x0a) // Literal name (len = 10)
    bytesIn.writeUtf8("custom-bar")
    bytesIn.writeByte(0x0d) // Literal value (len = 13)
    bytesIn.writeUtf8("custom-header")

        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)

      requestBody.writeUtf8("request A\n")
      requestBody.flush()
      val responseBody = response.body.source()
      assertThat(responseBody.readUtf8Line())
        .isEqualTo("response B")
      requestBody.writeUtf8("request C\n")
      requestBody.flush()
      assertThat(responseBody.readUtf8Line())
        .isEqualTo("response D")
      requestBody.writeUtf8("request E\n")
      requestBody.flush()

          sink
            .writeUtf8(headers.name(h))
            .write(COLONSPACE)
            .writeUtf8(headers.value(h))
            .write(CRLF)
        }
      }

      val contentType = body.contentType()
      if (contentType != null) {
        sink
          .writeUtf8("Content-Type: ")
          .writeUtf8(contentType.toString())
          .write(CRLF)
      }

          val chunkSize = minOf(body.size, maxChunkSize.toLong())
          bytesOut.writeHexadecimalUnsignedLong(chunkSize)
          bytesOut.writeUtf8("\r\n")
          bytesOut.write(body, chunkSize)
          bytesOut.writeUtf8("\r\n")
        }
        bytesOut.writeUtf8("0\r\n") // Last chunk. Trailers follow!
        this.body = bytesOut.toMockResponseBody()
      }

    /**

          override fun decode(reader: DerReader): String = reader.readUtf8String()

          override fun encode(
            writer: DerWriter,
            value: String,
          ) = writer.writeUtf8(value)
        },
    )

  /**
   * Permits alphanumerics, spaces, and these:
   *
   * ```
   *   ' () + , - . / : = ?
   * ```
   *