*
   * @since 20.0
   */
  public static void throwIfUnchecked(Throwable throwable) {
    checkNotNull(throwable);
    if (throwable instanceof RuntimeException) {
      throw (RuntimeException) throwable;
    }
    if (throwable instanceof Error) {
      throw (Error) throwable;
    }
  }

  /**
   * Propagates {@code throwable} exactly as-is, if and only if it is an instance of {@link

import static com.google.common.base.Throwables.getCausalChain;
import static com.google.common.base.Throwables.getCauseAs;
import static com.google.common.base.Throwables.getRootCause;
import static com.google.common.base.Throwables.getStackTraceAsString;
import static com.google.common.base.Throwables.lazyStackTrace;
import static com.google.common.base.Throwables.lazyStackTraceIsLazy;

    @Override
    public void suppress(Closeable closeable, Throwable thrown, Throwable suppressed) {
      suppressions.add(new Suppression(closeable, thrown, suppressed));
    }
  }

  /** Record of a call to suppress. */
  private static class Suppression {
    private final Closeable closeable;
    private final Throwable thrown;
    private final Throwable suppressed;

    Throwable throwable = thrown;

    // close closeables in LIFO order
    while (!stack.isEmpty()) {
      Closeable closeable = stack.removeFirst();
      try {
        closeable.close();
      } catch (Throwable e) {
        if (throwable == null) {
          throwable = e;
        } else {
          suppressor.suppress(closeable, throwable, e);
        }
      }
    }

    }

    /**
     * Outputs a log entry.
     *
     * @param throwable
     *            Exception. Must not be {@literal null}.
     */
    public void log(final Throwable throwable) {
        assertArgumentNotNull("throwable", throwable);

        error(throwable.getMessage(), throwable);
    }

    /**
     * Outputs a log entry.
     *
     * @param messageCode

        val addresses = Dns.SYSTEM.lookup(hostname)
        listOf(addresses[0])
      }

    private operator fun Throwable?.plus(throwable: Throwable): Throwable {
      if (this != null) {
        addSuppressed(throwable)
        return this
      }
      return throwable
    }
  }

    @Override
    public void suppress(Closeable closeable, Throwable thrown, Throwable suppressed) {
      suppressions.add(new Suppression(closeable, thrown, suppressed));
    }
  }

  /** Record of a call to suppress. */
  private static class Suppression {
    private final Closeable closeable;
    private final Throwable thrown;
    private final Throwable suppressed;

import static com.google.common.base.Throwables.getCausalChain;
import static com.google.common.base.Throwables.getCauseAs;
import static com.google.common.base.Throwables.getRootCause;
import static com.google.common.base.Throwables.getStackTraceAsString;
import static com.google.common.base.Throwables.lazyStackTrace;
import static com.google.common.base.Throwables.lazyStackTraceIsLazy;

    final Object result;
    final Throwable throwable;

    Response(String methodName, @Nullable Object result, @Nullable Throwable throwable) {
      this.methodName = methodName;
      this.result = result;
      this.throwable = throwable;
    }

    Object getResult() {
      if (throwable != null) {
        throw new AssertionError(throwable);
      }
      return result;
    }

  /**
   * Fails this future with the given Throwable if {@link #allMustSucceed} is true. Also, logs the
   * throwable if it is an {@link Error} or if {@link #allMustSucceed} is {@code true}, the
   * throwable did not cause this future to fail, and it is the first time we've seen that
   * particular Throwable.
   */
  private void handleException(Throwable throwable) {
    checkNotNull(throwable);

    if (allMustSucceed) {