@Test
  public void testEarlyoutOnTryResume() {
    CacheTransactionManager mgr = cache.getCacheTransactionManager();
    mgr.begin();
    TransactionId txId = mgr.suspend();
    mgr.resume(txId);
    mgr.commit();

    long start = System.currentTimeMillis();
    mgr.tryResume(txId, 10, TimeUnit.SECONDS);
    assertTrue("did not expect tryResume to block", System.currentTimeMillis() - start < 100);
  }
two threads suspend and resume a single transaction, while making changes.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/TXManagerImplJUnitTest.java