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 }