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