To use, assign an instance of this object to a local variable. When that variable falls out of scope (or is explicitly unset), the callback passed to the constructor will be invoked. This is useful, for example, to aid cleanup at the end of a function.

function f(&$x) {
  $x = 1;
  $_ = new \PhpLang\ScopeExit(function() use (&$x) { $x = 2; });
  // $x is still 1 at this point.
  return 42;
  // After the return, the local scope is cleaned up, the closure is invoked, and it's set to 2
}

f($a);
var_dump($a); // int(2)