public com.google.cloud.memorystore.v1.ZoneDistributionConfigOrBuilder
        getZoneDistributionConfigOrBuilder() {
      if (zoneDistributionConfigBuilder_ != null) {
        return zoneDistributionConfigBuilder_.getMessageOrBuilder();
      } else {
        return zoneDistributionConfig_ == null
            ? com.google.cloud.memorystore.v1.ZoneDistributionConfig.getDefaultInstance()
            : zoneDistributionConfig_;
      }
    }
<pre>
Optional. Immutable. Zone distribution configuration of the instance for
node allocation.
</pre>

<code>
.google.cloud.memorystore.v1.ZoneDistributionConfig zone_distribution_config = 18 [(.google.api.field_behavior) = OPTIONAL, (.google.api.field_behavior) = IMMUTABLE];
</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/Instance.java