Run an action and then, run a finalizer afterwards. The second action
will run whether or not an exception was raised by the first one. This
is like
bracket above, but can be used when you know you have
cleanup steps to take after your computation which
do have to
be run even if (especially if!) an exception is thrown but that that
cleanup doesn't depend on the result of that computation or the
resources used to do it. The return value
γ of the subsequent
action is ignored.