assertFinallyFailsWithException(closingFuture);
    waitUntilClosed(closingFuture);
    assertStillOpen(closeable1);
    assertClosed(closeable2, closeable3);
  }

  // We don't need to test the happy case for SuccessfulCombiner.call(Async) because it's the same
  // as Combiner.

  public void testWhenAllSucceed_call_failedInput() throws Exception {
    assertFinallyFailsWithException(

    assertFinallyFailsWithException(closingFuture);
    waitUntilClosed(closingFuture);
    assertStillOpen(closeable1);
    assertClosed(closeable2, closeable3);
  }

  // We don't need to test the happy case for SuccessfulCombiner.call(Async) because it's the same
  // as Combiner.

  public void testWhenAllSucceed_call_failedInput() throws Exception {
    assertFinallyFailsWithException(

      }

    /**
     * Configure this client to perform fast fallbacks by attempting multiple connections
     * concurrently, returning once any connection connects successfully.
     *
     * This implements Happy Eyeballs ([RFC 6555][rfc_6555]), balancing connect latency vs.
     * wasted resources.
     *
     * Defaults to enabled, call with [fastFallback] = false to revert to 4.x behaviour.
     *