o the type system that a variable or field of
a struct can have interior mutability, it must be wrapped in an UnsafeCell. This
does not in itself make it safe to perform interior mutability operations on
that value. You still must yourself ensure that mutual exclusion is upheld.</p>

<h1 id='liveness' class='section-header'><a href='#liveness'>Liveness</a></h1>
<p>Note: Liveness is not the same thing as a <em>lifetime</em>, which will be explained
in detail in the next section of this chapter.</p>

<p>Rough