lass</span> <span class="identifier">RatePolicy</span>
<span class="special">{</span>
    <span class="keyword">friend</span> <span class="keyword">class</span> <span class="identifier">rate_policy_access</span><span class="special">;</span>

    <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span>
    <span class="identifier">available_read_bytes</span><span class="special">();</span>

    <span class="identifier">std</span><span class="special">::</span>