void unlock(Class<?> clazz, ClassLock classLock) {
        synchronized (monitor) {
            if (classLock.equals(classLocks.get(clazz.getName()))) {
                classLocks.remove(clazz.getName());
                monitor.notifyAll();
            } else {
                throw new IllegalArgumentException("Lock has already been released");
            }
        }
    }
Locks key. This will block until the key is acquired or the interrupt condition is
no longer true. Condition is only checked at the start, everytime a lock is released
and when {@link #interrupt()} is called.

Users of this <b>must</b> close any lock acquired.

@throws LockInterruptException if interruptCondition returned false before
the lock could be acquired
vespajlib/src/main/java/com/yahoo/concurrent/classlock/ClassLocking.java