code: function Phantom(options) {
    if (!options) {
      throw new Error('options is required');
    }
  
    if (!options.port) {
      throw new Error('options.port is required');
    }
  
    this.options = options;
  
    this.child = null;
  }
docs: Phantom Constructor
  
  @param {Object} options
  @api public