metadata: ByteString,
      bufferMaxSize: Long,
    ): Relay {
      val randomAccessFile = RandomAccessFile(file, "rw")
      val result = Relay(randomAccessFile, upstream, 0L, metadata, bufferMaxSize)

      // Write a dirty header. That way if we crash we won't attempt to recover this.
      randomAccessFile.setLength(0L)
      result.writeHeader(PREFIX_DIRTY, -1L, -1L)

      return result
    }

class FileOperatorTest {
  @TempDir
  var tempDir: File? = null
  private var file: File? = null
  private var randomAccessFile: RandomAccessFile? = null

  @BeforeEach
  fun setUp() {
    file = File(tempDir, "test")
    randomAccessFile = RandomAccessFile(file, "rw")
  }

  @AfterEach
  fun tearDown() {
    randomAccessFile!!.close()
  }

  @Test
  fun read() {
    write("Hello, World".encodeUtf8())
    val operator =