docs: ThreadContext suspendTransaction() {
          ThreadContextProvider tranContextProvider = AccessController.doPrivileged(tranContextProviderAccessor);
          ThreadContext suspendedTranSnapshot = tranContextProvider == null ? null : tranContextProvider.captureThreadContext(XPROPS_SUSPEND_TRAN, null);
          if (suspendedTranSnapshot != null)
              suspendedTranSnapshot.taskStarting();
          return suspendedTranSnapshot;
      }