handle(object) {
    if (!object)
      throw new Error('Can only create handles for objects');
    if (typeof object === 'object' && handleSymbol in object)
      throw new Error('Can not return handle to handle.');
    const descriptor = this.describe_(object);
    const address = [this.worldId_, descriptor.name + '#' + (++this.lastHandleId_)];
    const handle = new Handle(address, address, descriptor, this);
    handle.object_ = object;
    this.idToHandle_.set(address[1], handle);
    return handle.proxy();
  }
Creates a handle to the object.
@param {!Object} object Object to create handle for
@return {!Object}