try {
            bodyRef.set(response.body.string())
          } catch (e: IOException) {
            // It is ok if this broke the stream.
            bodyRef.set("A")
            throw e // We expect to not loop into onFailure in this case.
          } finally {
            latch.countDown()
          }
        }
      },
    )
    latch.await()
    assertThat(bodyRef.get()).isEqualTo("A")

  private var coordinatorWaiting = false
  private var coordinatorWakeUpAt = 0L

  /**
   * When we need a new thread to run tasks, we call [Backend.execute]. A few microseconds later we
   * expect a newly-started thread to call [Runnable.run]. We shouldn't request new threads until
   * the already-requested ones are in service, otherwise we might create more threads than we need.
   *

      val success = webSocket.send(message)
      if (!success) break
      messageCount++
      val queueSize = webSocket.queueSize()
      assertThat(queueSize).isBetween(0L, messageCount * message.size)
      // Expect to fail before enqueueing 32 MiB.
      assertThat(messageCount).isLessThan(32L)
    }

    // Confirm all sent messages were received, followed by a client-initiated close.
    val server = serverListener.assertOpen()

   * delimited by 'null'.
   *
   * @param callerIsIdle true if the caller isn't sending any more bytes until the peer responds.
   *     This is true after a `Expect-Continue` request, false for duplex requests, and false for
   *     all other requests.
   */
  @Throws(IOException::class)
  fun takeHeaders(callerIsIdle: Boolean = false): Headers {
    this.withLock {

  }

  private fun testRequestMethod(
    requestMethod: String,
    expectCached: Boolean,
    withOverride: Boolean = false,
  ) {
    // 1. Seed the cache (potentially).
    // 2. Expect a cache hit or miss.
    server.enqueue(
      MockResponse.Builder()
        .addHeader("Expires: " + formatDate(1, TimeUnit.HOURS))
        .addHeader("X-Response-ID: 1")
        .build(),
    )

requests and remove a common source of non-null assertions (`!!`) on the response body.

The alpha releases in the 5.0.0 series have production-quality code and an unstable API. We expect
to make changes to the APIs introduced in 5.0.0-alpha.X. These releases are safe for production use
and 'alpha' strictly signals that we're still experimenting with some new APIs. If you're eager for

          httpHeaders.add(name, value)
        } else {
          throw IllegalStateException()
        }
        if (name == "expect" && value.equals("100-continue", ignoreCase = true)) {
          // Don't read the body unless we've invited the client to send it.
          readBody = false
        }
      }