return value;
    }

    /**
     * 値を設定します。
     *
     * @param value
     *            値
     */
    public void setValue(final T value) {
        this.value = value;
    }

    @Override
    public String toString() {
        return value.toString();
    }

            String name = (String) e.nextElement();
            String value = props.getProperty(name);
            if (value == null) {
                value = callback.apply(name);
            }
            if (name.startsWith(OVERRIDE_PREFIX)) {
                String overrideName = name.substring(OVERRIDE_PREFIX.length());
                props.put(overrideName, substVars(value, name, props, callback));
            } else {

            assert data == "Session cookie or query token value is: fakesession"
            data = websocket.receive_text()
            assert data == f"Message text was: {message}, for item ID: foo"
            message = "Message two"
            websocket.send_text(message)
            data = websocket.receive_text()
            assert data == "Session cookie or query token value is: fakesession"
            data = websocket.receive_text()

  /**
   * Returns the value associated with {@code key} in this cache, first loading that value if
   * necessary. No observable state associated with this cache is modified until loading completes.
   *
   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that

    }
  }

  /** getAndUpdate adds given value to current, and returns previous value */
  public void testGetAndUpdateWithSum() {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i : new int[] {0, SIZE - 1}) {
      for (double x : VALUES) {
        for (double y : VALUES) {
          aa.set(i, x);
          double z = aa.getAndUpdate(i, value -> value + y);
          assertBitEquals(x, z);

        if (value instanceof final LocalDateTime ldt) {
            final ZonedDateTime zdt = ZonedDateTime.of(ldt, ZoneId.systemDefault());
            super.addFieldToSource(sourceMap, field, DateTimeFormatter.ISO_INSTANT.format(zdt));
        } else {
            super.addFieldToSource(sourceMap, field, value);
        }
    }

    @Override

        if (value instanceof final LocalDateTime ldt) {
            final ZonedDateTime zdt = ZonedDateTime.of(ldt, ZoneId.systemDefault());
            super.addFieldToSource(sourceMap, field, DateTimeFormatter.ISO_INSTANT.format(zdt));
        } else {
            super.addFieldToSource(sourceMap, field, value);
        }
    }

    @Override

                                            <la:option value="25">25</la:option>
                                            <la:option value="50">50</la:option>
                                            <la:option value="100">100</la:option>
                                            <la:option value="200">500</la:option>
                                            <la:option value="1000">1000</la:option>

    return result;
  }

  /**
   * Returns the value associated with {@code key}, or zero if there is no value associated with
   * {@code key}.
   */
  public long get(K key) {
    AtomicLong atomic = map.get(key);
    return atomic == null ? 0L : atomic.get();
  }

  /**
   * Increments by one the value currently associated with {@code key}, and returns the new value.
   */
  @CanIgnoreReturnValue

// Singleton contains a pointer to T that must be set once.
// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v
}