public Builder setTtl(com.google.protobuf.Duration.Builder builderForValue) {
      if (ttlBuilder_ == null) {
        expiration_ = builderForValue.build();
        onChanged();
      } else {
        ttlBuilder_.setMessage(builderForValue.build());
      }
      expirationCase_ = 10;
      return this;
    }
<pre>
Input only. The TTL for this resource. The expiration time is computed:
now + TTL.
</pre>

<code>.google.protobuf.Duration ttl = 10 [(.google.api.field_behavior) = INPUT_ONLY];</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/CachedContent.java