*
   * {@snippet :
   * awaitDone(new FinalizationPredicate() {
   *   public boolean isDone() {
   *     return ref.get() == null;
   *   }
   * });
   * }
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  public static void awaitClear(WeakReference<?> ref) {
    awaitDone(() -> ref.get() == null);
  }

  /**

   *
   * {@snippet :
   * awaitDone(new FinalizationPredicate() {
   *   public boolean isDone() {
   *     return ref.get() == null;
   *   }
   * });
   * }
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  public static void awaitClear(WeakReference<?> ref) {
    awaitDone(() -> ref.get() == null);
  }

  /**

import static com.google.common.primitives.Bytes.concat;
import static com.google.common.testing.GcFinalization.awaitClear;
import static com.google.common.testing.GcFinalization.awaitDone;
import static com.google.common.truth.Truth.assertThat;
import static java.lang.Math.min;
import static java.nio.file.attribute.PosixFilePermission.OWNER_READ;

          @Override
          protected void finalize() {
            future.set(null);
          }
        };
    unused = null; // Hint to the JIT that unused is unreachable
    GcFinalization.awaitDone(future);
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
  }

  public void testAwaitDone_future_cancel() {
    SettableFuture<@Nullable Void> future = SettableFuture.create();

          @Override
          protected void finalize() {
            future.set(null);
          }
        };
    unused = null; // Hint to the JIT that unused is unreachable
    GcFinalization.awaitDone(future);
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
  }

  public void testAwaitDone_future_cancel() {
    SettableFuture<@Nullable Void> future = SettableFuture.create();

    frq = null;
  }

  @Test
  public void testFinalizeReferentCalled() {
    MockReference reference = new MockReference(frq = new FinalizableReferenceQueue());

    GcFinalization.awaitDone(() -> reference.finalizeReferentCalled);
  }

  static class MockReference extends FinalizableWeakReference<Object> {

    volatile boolean finalizeReferentCalled;

    MockReference(FinalizableReferenceQueue frq) {

    }
  }

  /** For testing: sends a ping and waits for a pong. */
  @Throws(InterruptedException::class)
  fun writePingAndAwaitPong() {
    writePing()
    awaitPong()
  }

  /** For testing: sends a ping to be awaited with [awaitPong]. */
  @Throws(InterruptedException::class)
  fun writePing() {
    withLock {
      awaitPingsSent++
    }

    // 0x4f 0x4b 0x6f 0x6b is "OKok".

        throw ConnectionShutdownException()
      }
    }
    connection.writePing()
    connection.shutdown(ErrorCode.PROTOCOL_ERROR)
    assertThat(connection.openStreamCount()).isEqualTo(1)
    connection.awaitPong() // Prevent the peer from exiting prematurely.

    // Verify the peer received what was expected.
    val synStream1 = peer.takeFrame()
    assertThat(synStream1.type).isEqualTo(Http2.TYPE_HEADERS)