public Builder addForwardingRules(
        com.google.cloud.vmwareengine.v1.DnsForwarding.ForwardingRule value) {
      if (forwardingRulesBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        ensureForwardingRulesIsMutable();
        forwardingRules_.add(value);
        onChanged();
      } else {
        forwardingRulesBuilder_.addMessage(value);
      }
      return this;
    }
<pre>
Required. List of domain mappings to configure
</pre>

<code>
repeated .google.cloud.vmwareengine.v1.DnsForwarding.ForwardingRule forwarding_rules = 4 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/DnsForwarding.java