public Builder addSecondaryInstances(
        int index,
        com.google.cloud.memorystore.v1.CrossInstanceReplicationConfig.RemoteInstance value) {
      if (secondaryInstancesBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        ensureSecondaryInstancesIsMutable();
        secondaryInstances_.add(index, value);
        onChanged();
      } else {
        secondaryInstancesBuilder_.addMessage(index, value);
      }
      return this;
    }
<pre>
Optional. List of secondary instances that are replicating from this
primary instance.

This field is only set for a primary instance.
</pre>

<code>
repeated .google.cloud.memorystore.v1.CrossInstanceReplicationConfig.RemoteInstance secondary_instances = 3 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/CrossInstanceReplicationConfig.java