public Builder setVectorDistanceThreshold(double value) {

        vectorDbThresholdCase_ = 3;
        vectorDbThreshold_ = value;
        onChanged();
        return this;
      }
<pre>
Optional. Only returns contexts with vector distance smaller than the
threshold.
</pre>

<code>double vector_distance_threshold = 3 [(.google.api.field_behavior) = OPTIONAL];
</code>

@param value The vectorDistanceThreshold to set.
@return This builder for chaining.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/RagRetrievalConfig.java