dfn>state</dfn>, which is one of <code>{started, paused, stopped}</code>.</li>
        <li>
          A <dfn>sample interval</dfn>, defined as the periodicity at which the session obtains samples.
          <p class="note">
          The UA is NOT REQUIRED to take samples at this rate. However, it is
          RECOMMENDED that sampling is prioritized to take samples at this rate to
          produce higher quality traces.
          </p>
        </li>
        <li>An <dfn data-cite="!ECMA-262#agent">agent</df