docs: public java.util.List<RouteFilterPrefix> getExistingAllowedPrefixesToDirectConnectGateway() {
          if (existingAllowedPrefixesToDirectConnectGateway == null) {
              existingAllowedPrefixesToDirectConnectGateway = new com.amazonaws.internal.SdkInternalList<RouteFilterPrefix>();
          }
          return existingAllowedPrefixesToDirectConnectGateway;
      }