   <p>In general, adaptation prevents the chain from reaching a stationary
distribution, so obtaining consistent samples requires <code>num_adaptation_steps</code>
be set to a value somewhat smaller than the number of burnin steps.
However, it may sometimes be helpful to set <code>num_adaptation_steps</code> to a larger
value during development in order to inspect the behavior of the chain during
adaptation.</p>
<p>The step size is assumed to broadcast with the chain state, potentially having
leading dimens