synchronized void cancelTransaction(final PingPongTransaction tx, final DOMDataReadWriteTransaction frontendTx) {
// Attempt to unlock the operation.
final boolean lockedMatch = LOCKED_UPDATER.compareAndSet(this, tx, null);
synchronized void cancelTransaction(final PingPongTransaction tx, final DOMDataReadWriteTransaction frontendTx) {
// Attempt to unlock the operation.
final boolean lockedMatch = LOCKED_UPDATER.compareAndSet(this, tx, null);