double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigDecimal.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

    double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigInteger.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

  val request3 = server.takeRequest()
  assertEquals("/v1/chat/messages/3", request3.url.encodedPath)

  // Shut down the server. Instances cannot be reused.
  server.close()
}
```

Your unit tests might move the `server` into a field so you can shut it down
from your test's `tearDown()`.

### API

#### MockResponse

 */

package com.google.common.math;

import static java.math.BigInteger.ONE;
import static java.math.BigInteger.ZERO;
import static java.math.RoundingMode.CEILING;
import static java.math.RoundingMode.DOWN;
import static java.math.RoundingMode.FLOOR;
import static java.math.RoundingMode.HALF_DOWN;
import static java.math.RoundingMode.HALF_EVEN;
import static java.math.RoundingMode.HALF_UP;

     */
    public void shutdown() {
        shutdownListener.onShutdown();
    }

    /**
     * Adds a shutdown listener to be notified when the executor is shutting down.
     *
     * @param listener the shutdown listener to add
     */
    public void addShutdownListener(final ShutdownListener listener) {
        shutdownListener = listener;
    }

    /**

        if (endpointGroup != null) {
            try {
                // In real implementation: endpointGroup.close();
                log.info("DiSNI RDMA provider shut down");
            } catch (Exception e) {
                log.error("Error shutting down DiSNI", e);
            } finally {
                endpointGroup = null;
                endpoint = null;
                initialized = false;
            }
        }

To use, first add this library as a test dependency:

```
testImplementation("com.squareup.okhttp3:mockwebserver3-junit5:5.3.0")
```

Annotate fields in test classes with `@StartStop`. The server will be started and shut down
automatically.

```
class MyTest {

  @StartStop
  public final MockWebServer server = new MockWebServer();

  @Test
  void test() {
    ...
  }
}
```

Requirements
------------

```
@Rule public final MockWebServerRule serverRule = new MockWebServerRule();
```

The `serverRule` field has a `server` field. It is an instance of `MockWebServer`. That instance
will be shut down automatically after the test runs.

For Kotlin, the `@JvmField` annotation is also necessary:

```
@JvmField @Rule val serverRule = MockWebServerRule()

                  service.awaitTermination(terminationTimeout, timeUnit);
                } catch (InterruptedException ignored) {
                  // We're shutting down anyway, so just ignore.
                }
              }));
    }

    @VisibleForTesting
    void addShutdownHook(Thread hook) {
      Runtime.getRuntime().addShutdownHook(hook);
    }
  }

final class SingletonImmutableSet<E> extends ImmutableSet<E> {
  // We deliberately avoid caching the asList and hashCode here, to ensure that with
  // compressed oops, a SingletonImmutableSet packs all the way down to the optimal 16 bytes.

  final transient E element;

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

  @Override
  public int size() {
    return 1;