}

          @Override
          public void onFailure(Throwable t) {
            failureCalls[0]++;
          }
        };
    addCallback(future, callback, directExecutor());
    future.set(result);
    assertEquals(result, future.get());
    assertThat(successCalls[0]).isEqualTo(1);
    assertThat(failureCalls[0]).isEqualTo(0);
  }

  public void testOnSuccessThrowsError() throws Exception {

*   When you contribute a new feature to TensorFlow, the maintenance burden is
    (by default) transferred to the TensorFlow team. This means that the benefit
    of the contribution must be compared against the cost of maintaining the
    feature.
*   Full new features (e.g., a new op implementing a cutting-edge algorithm)
    typically will live in

  }

  @Test
  public void nodeOrder_natural() {
    MutableGraph<Integer> graph =
        GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();

    addNodes(graph);

    assertThat(graph.nodeOrder()).isEqualTo(ElementOrder.sorted(Ordering.<Integer>natural()));
    assertThat(graph.nodes()).containsExactly(1, 3, 4).inOrder();
  }

  @Test
  public void nodeOrder_sorted() {

            .allowsSelfLoops(true)
            .nodeOrder(ElementOrder.<String>natural())
            .immutable()
            .build();

    assertThat(emptyGraph.isDirected()).isTrue();
    assertThat(emptyGraph.allowsSelfLoops()).isTrue();
    assertThat(emptyGraph.nodeOrder()).isEqualTo(ElementOrder.<String>natural());
  }

  /**

          }
        };

    AsyncCallable<String> asyncCallable =
        Callables.asAsyncCallable(callable, newDirectExecutorService());

    ListenableFuture<String> future = asyncCallable.call();
    assertSame(expected, future.get());
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable_exception() throws Exception {
    Exception expected = new IllegalArgumentException();

            .allowsSelfLoops(true)
            .nodeOrder(ElementOrder.<String>natural())
            .immutable()
            .build();

    assertThat(emptyGraph.isDirected()).isTrue();
    assertThat(emptyGraph.allowsSelfLoops()).isTrue();
    assertThat(emptyGraph.nodeOrder()).isEqualTo(ElementOrder.<String>natural());
  }

  /**

        try {
          assertEquals("hello", data);
          future.complete(null);
        } catch (Exception e) {
          future.completeExceptionally(e);
        }
      }

      @Override
      public void onClosed(@NotNull EventSource eventSource) {
        future.completeExceptionally(new IllegalStateException("closed"));
      }

      @Override

## How to test this PR?


## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Optimization (provides speedup with no functional changes)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Checklist:
- [ ] Fixes a regression (If yes, please add `commit-id` or `PR #` here)

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

      Future<?> possiblyIgnoredError = threadPool.submit(new Producer(q, 20));
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError1 = threadPool.submit(new Producer(q, 20));
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored