messaging-activemq/src/main/java/org/wildfly/extension/messaging/activemq/deployment/injection/InjectedJMSContext.java
private TransactionSynchronizationRegistry getTransactionSynchronizationRegistry() {
        TransactionSynchronizationRegistry cachedTSR = transactionSynchronizationRegistry;
        if (cachedTSR == null) {
            cachedTSR = (TransactionSynchronizationRegistry) lookup(TRANSACTION_SYNCHRONIZATION_REGISTRY_LOOKUP);
            transactionSynchronizationRegistry = cachedTSR;
        }
        return cachedTSR;
    }
private TransactionSynchronizationRegistry getTransactionSynchronizationRegistry() {
        TransactionSynchronizationRegistry cachedTSR = transactionSynchronizationRegistry;
        if (cachedTSR == null) {
            cachedTSR = (TransactionSynchronizationRegistry) lookup(TRANSACTION_SYNCHRONIZATION_REGISTRY_LOOKUP);
            transactionSynchronizationRegistry = cachedTSR;
        }
        return cachedTSR;
    }
lookup the transactionSynchronizationRegistry and cache it.