public SynthesisTask withEngine(Engine engine) {
        this.engine = engine.toString();
        return this;
    }
<p>
Specifies the engine (<code>standard</code>, <code>neural</code>, <code>long-form</code> or
<code>generative</code>) for Amazon Polly to use when processing input text for speech synthesis. Using a voice
that is not supported for the engine selected will result in an error.
</p>

@param engine
       Specifies the engine (<code>standard</code>, <code>neural</code>, <code>long-form</code> or
       <code>generative</code>) for Amazon Polly to use when processing input text for speech synthesis. Using a
       voice that is not supported for the engine selected will result in an error.
@return Returns a reference to this object so that method calls can be chained together.
@see Engine
aws-java-sdk-polly/src/main/java/com/amazonaws/services/polly/model/SynthesisTask.java