trailers { error("trailers not available") }
      }

    assertFailsWith<IllegalStateException>(message = "trailers not available") {
      response.trailers()
    }
  }

  @Test
  fun worksIfTrailersSet() {
    val response =
      newResponse("".toResponseBody()) {
        trailers {
          Headers.headersOf("a", "b")
        }
      }

    assertThat(response.trailers()["a"]).isEqualTo("b")
  }