private void ensureAutoscalingMetricSpecsIsMutable() {
      if (!((bitField0_ & 0x00000010) != 0)) {
        autoscalingMetricSpecs_ =
            new java.util.ArrayList<com.google.cloud.vertexai.api.AutoscalingMetricSpec>(
                autoscalingMetricSpecs_);
        bitField0_ |= 0x00000010;
      }
    }
<pre>
Optional. Number of required available replicas for the deployment to
succeed. This field is only needed when partial model deployment/mutation
is desired. If set, the model deploy/mutate operation will succeed once
available_replica_count reaches required_replica_count, and the rest of
the replicas will be retried. If not set, the default
required_replica_count will be min_replica_count.
</pre>

<code>int32 required_replica_count = 9 [(.google.api.field_behavior) = OPTIONAL];</code>

@return This builder for chaining.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/DedicatedResources.java