static AutoCloseable tempVerboseLock(S purpose default "", Lock lock) {
  if (lock == null) null;
  S desc = dropPrefix("java.util.concurrent.locks.", str(lock)) + appendIfNempty2(" for ", purpose);
  print("Locking " + desc + " in " + currentThread());
  lock(lock);
  print_noFail("Locked " + desc + " in " + currentThread());
  ret () -> {
    print_noFail("Unlocking " + desc + " in " + currentThread());
    unlock(lock);
  };
}