whole_func_string: function Sender(options) {
    EventEmitter.call(this);
    _.extend(this, _.defaults(options || {}, {
      retries: 4
    }));
  }
func_code_string: function Sender(options) {
    EventEmitter.call(this);
    _.extend(this, _.defaults(options || {}, {
      retries: 4
    }));
  }
func_documentation_string: Create a new GCM sender.
  
  @param {object} options
  @param {string} options.apiKey
  @param {number} options.retries