url = server.url("/"),
          body =
            object : ForwardingRequestBody(transferKind.newRequestBody("def")) {
              override fun writeTo(sink: BufferedSink) {
                sinkReference.set(sink)
                super.writeTo(sink)
              }
            },
        ),
      )
    assertThat(readAscii(response.body.byteStream(), Int.MAX_VALUE))
      .isEqualTo("abc")

    // Call 1: set a deadline on the request body.
    val requestBody1: RequestBody =
      object : RequestBody() {
        override fun contentType(): MediaType = "text/plain".toMediaType()

        override fun writeTo(sink: BufferedSink) {
          sink.writeUtf8("abc")
          sink.timeout().deadline(5, TimeUnit.SECONDS)
        }
      }
    val request1 =
      Request.Builder()
        .url(server.url("/"))

  ): MockResponse.Builder {
    val response = builder.build()
    builder.socketPolicy(DisconnectAtEnd)
    val headers = response.headers
    val fullBody = Buffer()
    response.body!!.writeTo(fullBody)
    val truncatedBody = Buffer()
    truncatedBody.write(fullBody, numBytesToKeep.toLong())
    builder.body(truncatedBody)
    builder.headers(headers)
    return builder
  }