message: Mark sync param as optional so that my IDE will stop complaining.
diff: @@ -16,13 +16,13 @@ limitations under the License.
  'use strict';
  -var flux = require("flux");
  +const flux = require("flux");
  class MatrixDispatcher extends flux.Dispatcher {
  /**
  * @param {Object} payload Required. The payload to dispatch.
  * Must contain at least an 'action' key.
  - * @param {boolean} sync Optional. Pass true to dispatch
  + * @param {boolean=} sync Optional. Pass true to dispatch
  * synchronously. This is useful for anything triggering
  * an operation that the browser requires user interaction
  * for.
  