// has been used.
// The returned reader contains the payload.
func waitForHTTPResponse(respBody io.Reader) (io.Reader, error) {
	reader := bufio.NewReader(respBody)
	for {
		b, err := reader.ReadByte()
		if err != nil {
			return nil, err
		}
		// Check if we have a response ready or a filler byte.
		switch b {
		case 0:
			return reader, nil
		case 1:
			errorText, err := io.ReadAll(reader)

HSPLokio/Buffer;->getByte(J)B
HSPLokio/Buffer;->indexOfElement(Lokio/ByteString;)J
HSPLokio/Buffer;->rangeEquals(JLokio/ByteString;)Z
HSPLokio/Buffer;->read(Lokio/Buffer;J)J
HSPLokio/Buffer;->read([BII)I
HSPLokio/Buffer;->readByte()B
HSPLokio/Buffer;->readByteArray(J)[B
HSPLokio/Buffer;->readByteString()Lokio/ByteString;
HSPLokio/Buffer;->readByteString(J)Lokio/ByteString;
HSPLokio/Buffer;->readInt()I
HSPLokio/Buffer;->readIntLe()I

    val bodySource = response.body.source()
    assertThat(bodySource.readByte()).isEqualTo('d'.code.toByte())

    // The second byte of this request will be delayed by 750ms so we should time out after 250ms.
    val startNanos = System.nanoTime()
    bodySource.use {
      assertFailsWith<IOException> {
        bodySource.readByte()
      }.also { expected ->
        // Timed out as expected.

    val response1 = get(server.url("/"))
    val source = response1.body.source()
    assertThat(source.readUtf8(5)).isEqualTo("ABCDE")
    source.close()
    assertFailsWith<IllegalStateException> {
      source.readByte()
    }
    assertThat(cache.writeAbortCount()).isEqualTo(1)
    assertThat(cache.writeSuccessCount()).isEqualTo(0)
    val response2 = get(server.url("/"))

pkg io, method (*SectionReader) Size() int64
pkg io, type ByteReader interface { ReadByte }
pkg io, type ByteReader interface, ReadByte() (uint8, error)
pkg io, type ByteScanner interface { ReadByte, UnreadByte }
pkg io, type ByteScanner interface, ReadByte() (uint8, error)
pkg io, type ByteScanner interface, UnreadByte() error
pkg io, type Closer interface { Close }