public java.lang.String getApiKeySecretVersion() {
        java.lang.Object ref = apiKeySecretVersion_;
        if (!(ref instanceof java.lang.String)) {
          com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
          java.lang.String s = bs.toStringUtf8();
          apiKeySecretVersion_ = s;
          return s;
        } else {
          return (java.lang.String) ref;
        }
      }
<pre>
Required. The SecretManager secret version resource name storing API key.
e.g. projects/{project}/secrets/{secret}/versions/{version}
</pre>

<code>
string api_key_secret_version = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
</code>

@return The apiKeySecretVersion.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ApiAuth.java