private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig,
            com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig.Builder,
            com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfigOrBuilder>
        getApiKeyConfigFieldBuilder() {
      if (apiKeyConfigBuilder_ == null) {
        if (!(authConfigCase_ == 1)) {
          authConfig_ = com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig.getDefaultInstance();
        }
        apiKeyConfigBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig,
                com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig.Builder,
                com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfigOrBuilder>(
                (com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig) authConfig_,
                getParentForChildren(),
                isClean());
        authConfig_ = null;
      }
      authConfigCase_ = 1;
      onChanged();
      return apiKeyConfigBuilder_;
    }
<pre>
The API secret.
</pre>

<code>.google.cloud.vertexai.v1.ApiAuth.ApiKeyConfig api_key_config = 1;</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ApiAuth.java