class Concurrent::RubyThreadLocalVar

def value=(value)
  me = Thread.current
  # We could keep the thread-local arrays in a hash, keyed by Thread
  # But why? That would require locking
  # Using Ruby's built-in thread-local storage is faster
  unless array = get_threadlocal_array(me)
    array = set_threadlocal_array([], me)
    LOCK.synchronize { ARRAYS[array.object_id] = array }
    ObjectSpace.define_finalizer(me, self.class.thread_finalizer(array))
  end
  array[@index] = (value.nil? ? NULL : value)
  value
end