}

      socket.sleepWhileOpen(response.headersDelayNanos)
      stream.writeHeaders(response.toHttp2Headers(), outFinished, flushHeaders)

      if (trailers.size > 0) {
        stream.enqueueTrailers(trailers)
      }
      pushPromises(stream, request, response.pushPromises)
      if (body != null) {
        socket.sleepWhileOpen(bodyDelayNanos)
        val responseBodySink =

  private fun serverTruncatesRequestButTrailersCanStillBeRead(http2: Boolean) {
    val mockResponse =
      MockResponse
        .Builder()
        .doNotReadRequestBody()
        .trailers(headersOf("caboose", "xyz"))

    // Trailers always work for HTTP/2, but only for chunked bodies in HTTP/1.
    if (http2) {
      mockResponse.body("abc")
    } else {
      mockResponse.chunkedBody("abc", 1)
    }

    var trailers: Headers = mockResponse.trailers
    mockResponse = mockResponse.clearHeaders()
    mockResponse = mockResponse.addHeader("")
    mockResponse = mockResponse.addHeader("", "")
    mockResponse = mockResponse.addHeaderLenient("", Any())
    mockResponse = mockResponse.setHeader("", Any())
    mockResponse.headers = headersOf()
    mockResponse.trailers = headersOf()

    throwing in 5.0.0, we inadvertently removed the ability for callers to peek the trailers
    (by catching the `IllegalStateException` if they weren't available). This new API restores that
    capability.

 *  Fix: Don't crash on `trailers()` if the response doesn't have a body. We broke [Retrofit] users

interface ExchangeCodec {
  /** The connection or CONNECT tunnel that owns this codec. */
  val carrier: Carrier

  /** Returns true if the response body and (possibly empty) trailers have been received. */
  val isResponseComplete: Boolean

  /** The socket that carries this exchange. */
  val socket: Socket

  /** Returns an output stream where the request body can be streamed. */

            }
            val responseBody = exchange.openResponseBody(response)
            response
              .newBuilder()
              .body(responseBody)
              .trailers(
                object : TrailersSource {
                  override fun peek() = exchange.peekTrailers()

                  override fun get(): Headers {
                    val source = responseBody.source()

  fun readLine(): String {
    val line = source.readUtf8LineStrict(headerLimit)
    headerLimit -= line.length.toLong()
    return line
  }

  /** Reads headers or trailers. */
  fun readHeaders(): Headers {
    val result = Headers.Builder()
    while (true) {
      val line = readLine()
      if (line.isEmpty()) break
      result.addLenient(line)
    }
    return result.build()

    var trailers: Headers = mockResponse.trailers
    mockResponse = mockResponse.clearHeaders()
    mockResponse = mockResponse.addHeader("")
    mockResponse = mockResponse.addHeader("", "")
    mockResponse = mockResponse.addHeaderLenient("", Any())
    mockResponse = mockResponse.setHeader("", Any())
    mockResponse.headers = headersOf()
    mockResponse.trailers = headersOf()

        .exhaustResponse()
    server.enqueue(
      MockResponse
        .Builder()
        .clearHeaders()
        .addHeader("h1", "v1")
        .addHeader("h2", "v2")
        .trailers(headersOf("trailers", "boom"))
        .socketHandler(body)
        .build(),
    )
    val call =
      client.newCall(
        Request
          .Builder()
          .url(server.url("/"))
          .build(),

        // header names must be lowercase.
        val name = headers.name(i).lowercase(Locale.US)
        if (name !in HTTP_2_SKIPPED_REQUEST_HEADERS ||
          name == TE &&
          headers.value(i) == "trailers"
        ) {
          result.add(Header(name, headers.value(i)))
        }
      }
      return result
    }

    /** Returns headers for a name value block containing an HTTP/2 response. */