cs-release-1.11/dev/stream/state/state.html#using-keyed-state">use</a>
<code>MapState</code> to store the individual events of the window. In order to allow
efficient clean-up of the out-of-scope events, we will utilize event
timestamps as the <code>MapState</code> keys.</p>
<p>In a general case, we have to take into account the fact that there
might be different events with exactly the same timestamp, therefore
instead of individual Transaction per key(timestamp) we will store sets.</p>
<div class="highlig