outFrames.add(OutFrame(frameCount++, bytesOut.size, false))
    return writer
  }

  /**
   * Shortens the last frame from its original length to `length`. This will cause the peer to
   * close the socket as soon as this frame has been written; otherwise the peer stays open until
   * explicitly closed.
   */
  fun truncateLastFrame(length: Int): Http2Writer {
    val lastFrame = outFrames.removeAt(outFrames.size - 1)

    val metadataBuffer = Buffer()
    metadataBuffer.write(metadata)

    val fileOperator = FileOperator(file!!.channel)
    fileOperator.write(FILE_HEADER_SIZE + upstreamSize, metadataBuffer, metadata.size.toLong())
  }

  @Throws(IOException::class)
  fun commit(upstreamSize: Long) {
    // Write metadata to the end of the file.
    writeMetadata(upstreamSize)
    file!!.channel.force(false)

 *  Fix: Reliably update and invalidate the disk cache on windows. As originally designed our
    internal `DiskLruCache` assumes an inode-like file system, where it's fine to delete files that
    are currently being read or written. On Windows the file system forbids this so we must be more
    careful when deleting and renaming files.

 *  Fix: Don't crash on Java 8u252 which introduces an API previously found only on Java 9 and

   *
   * For streaming requests with a body, headers must be prepared **before** the output stream has
   * been written to. Otherwise the body would need to be buffered!
   *
   * For non-streaming requests with a body, headers must be prepared **after** the output stream
   * has been written to and closed. This ensures that the `Content-Length` header field receives
   * the proper value.
   */

      editor = snapshot.edit() ?: return // edit() returns null if snapshot is not current.
      entry.writeTo(editor)
      editor.commit()
    } catch (_: IOException) {
      abortQuietly(editor)
    }
  }

  private fun abortQuietly(editor: DiskLruCache.Editor?) {
    // Give up because the cache cannot be written.
    try {
      editor?.abort()
    } catch (_: IOException) {
    }
  }

  /**

  fun fromDer(byteString: ByteString): T {
    val buffer = Buffer().write(byteString)
    val reader = DerReader(buffer)
    return fromDer(reader)
  }

  /**
   * Writes [value] to this adapter, unless it is the default value and can be safely omitted.
   *
   * If this does write a value, it will write a tag and a length and a full value.
   */
  fun toDer(
    writer: DerWriter,
    value: T,
  )

import org.junit.jupiter.api.Assertions.assertTrue

/** A duplex request body that keeps the provided sinks so they can be written to later.  */
class AsyncRequestBody : RequestBody() {
  private val requestBodySinks: BlockingQueue<BufferedSink> = LinkedBlockingQueue()

  override fun contentType(): MediaType? = null

  override fun writeTo(sink: BufferedSink) {
    requestBodySinks.add(sink)
  }

  override fun isDuplex(): Boolean = true

    assertOnFileDescriptor(content = "Hello") { fd ->
      val requestBody = fd.toRequestBody()

      val buffer = Buffer()
      requestBody.writeTo(buffer)
      assertThat(buffer.readUtf8()).isEqualTo("Hello")

      assertThrows(IOException::class.java) {
        requestBody.writeTo(Buffer())
      }
    }
  }

  @Test
  fun testFileDescriptorAfterClose() {

      )

    call.execute().use { response ->
      assertThat(response.body.string()).isEqualTo("abc")
      val requestBodyOut = requestBody.takeSink()
      assertFailsWith<IOException> {
        SlowRequestBody.writeTo(requestBodyOut)
      }
      assertFailsWith<IOException> {
        requestBodyOut.close()
      }
    }

    // Confirm that the connection pool was not corrupted by making another call.

        try {
          cache.remove(networkRequest)
        } catch (_: IOException) {
          // The cache cannot be written.
        }
      }
    }

    return response
  }

  /**
   * Returns a new source that writes bytes to [cacheRequest] as they are read by the source
   * consumer. This is careful to discard bytes left over when the stream is closed; otherwise we