@java.lang.Override
    public com.google.cloud.vertexai.api.FunctionCall getFunctionCall() {
      if (functionCallBuilder_ == null) {
        if (dataCase_ == 5) {
          return (com.google.cloud.vertexai.api.FunctionCall) data_;
        }
        return com.google.cloud.vertexai.api.FunctionCall.getDefaultInstance();
      } else {
        if (dataCase_ == 5) {
          return functionCallBuilder_.getMessage();
        }
        return com.google.cloud.vertexai.api.FunctionCall.getDefaultInstance();
      }
    }
<pre>
Optional. A predicted [FunctionCall] returned from the model that
contains a string representing the [FunctionDeclaration.name] with the
parameters and their values.
</pre>

<code>
.google.cloud.vertexai.v1.FunctionCall function_call = 5 [(.google.api.field_behavior) = OPTIONAL];
</code>

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