code: public static FlowContext deserializeNativeFlowContext(final String flowContextString) {
  
          if (flowContextString == null) {
              return null;
          }
  
          final FlowContext flowContext =
                  FlowContextImpl.deserializeNativeFlowContext(flowContextString);
          addFlowContext(flowContext);
  
          return flowContext;
      }
docs: De-serialize a Sting to FlowContext object and add it to ThreadLocal.
  If there is a FlowContext in the ThreadLocal it will be overridden.
  
  @param flowContextString - a String represents FlowContext object.
  @return flowContext or null if flowContextString is not valid.