<span class="type-annotation"><a href="dart-async/CreateTimerHandler.html">CreateTimerHandler</a></span> <span class="parameter-name">createTimer</span>: <span class="default-value">null</span>, </span> <span class="parameter" id="from-param-createPeriodicTimer"><span class="type-annotation"><a href="dart-async/CreatePeriodicTimerHandler.html">CreatePeriodicTimerHandler</a></span> <span class="parameter-name">createPeriodicTimer</span>: <span class="default-value">null</span>, </span> <span class="parameter