docs: public DirectConnectGatewayAssociationProposal withExistingAllowedPrefixesToDirectConnectGateway(
              RouteFilterPrefix... existingAllowedPrefixesToDirectConnectGateway) {
          if (this.existingAllowedPrefixesToDirectConnectGateway == null) {
              setExistingAllowedPrefixesToDirectConnectGateway(new com.amazonaws.internal.SdkInternalList<RouteFilterPrefix>(
                      existingAllowedPrefixesToDirectConnectGateway.length));
          }
          for (RouteFilterPrefix ele : existingAllowedPrefixesToDirectConnectGateway) {
              this.existingAllowedPrefixesToDirectConnectGateway.add(ele);
          }
          return this;
      }