docs: private Long performCommit(JPACommit commit) throws EDBException {
          synchronized (entityManager) {
              long timestamp = System.currentTimeMillis();
              try {
                  beginTransaction();
                  persistCommitChanges(commit, timestamp);
                  commitTransaction();
              } catch (Exception ex) {
                  try {
                      rollbackTransaction();
                  } catch (Exception e) {
                      throw new EDBException("Failed to rollback transaction to EDB", e);
                  }
                  throw new EDBException("Failed to commit transaction to EDB", ex);
              }
              return timestamp;
          }
      }