public Builder ipv4(@Nullable Output<String> ipv4) {
            $.ipv4 = ipv4;
            return this;
        }
@param ipv4 IPv4 defines an IPv4 IP block in CIDR notation(e.g. &#34;10.0.0.0/8&#34;). At least one of IPv4 and IPv6 must be specified. This field is immutable.

@return builder
sdk/java/src/main/java/com/pulumi/kubernetes/networking/v1alpha1/inputs/ClusterCIDRSpecPatchArgs.java