docs: void initialize()
      {
          if (m_backend == BackendTarget.NONE) {
              m_non_voltdb_backend = null;
              m_ee = new MockExecutionEngine();
          }
          else if (m_backend == BackendTarget.HSQLDB_BACKEND) {
              m_non_voltdb_backend = HsqlBackend.initializeHSQLBackend(m_siteId, m_context);
              m_ee = new MockExecutionEngine();
          }
          else if (m_backend == BackendTarget.POSTGRESQL_BACKEND) {
              m_non_voltdb_backend = PostgreSQLBackend.initializePostgreSQLBackend(m_context);
              m_ee = new MockExecutionEngine();
          }
          else if (m_backend == BackendTarget.POSTGIS_BACKEND) {
              m_non_voltdb_backend = PostGISBackend.initializePostGISBackend(m_context);
              m_ee = new MockExecutionEngine();
          }
          else {
              m_non_voltdb_backend = null;
              m_ee = initializeEE();
          }
          m_ee.loadFunctions(m_context);
  
          m_snapshotter = new SnapshotSiteProcessor(m_scheduler,
          m_snapshotPriority,
          new SnapshotSiteProcessor.IdlePredicate() {
              @Override
              public boolean idle(long now) {
                  return (now - 5) > m_lastTxnTime;
              }
          });
      }