span> <span class="keyword">of</span> <a href="#type-atom_type">atom_type</a></span></code></li><li id="type-type_.BitString" class="def variant constructor anchored"><a href="#type-type_.BitString" class="anchor"></a><code><span>| </span><span><span class="constructor">BitString</span> <span class="keyword">of</span> </span><span>{</span></code><ol><li id="type-type_.start_size" class="def record field anchored"><a href="#type-type_.start_size" class="anchor"></a><code><span>start_size : int;</span></code>