code: public LocalTransactionCoordinator suspend()
      {
          if (tc.isEntryEnabled()) Tr.entry(tc, "suspend", this);
  
          final LocalTranCoordImpl ltc = _coord;
          if (ltc != null)
          {
              _coord = null;
              ltc.suspend();           // suspend any native context
              
              invokeEventListener(ltc, UOWEventListener.SUSPEND, null);
          }
  
          if (tc.isEntryEnabled()) Tr.exit(tc, "suspend", ltc);
          return ltc;
      }
docs: Disassociates the LTC scope from the thread.
  
  @return the LocalTransactionCoordinator instance representing the LTC scope
  disassociated from the thread. If there was no LTC scope, returns null.