@java.lang.Override
    public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
      return super.setUnknownFields(unknownFields);
    }
<pre>
The progress of the most recent processing update in percentage, ie. 70.0%.
</pre>

<code>double progress_percentage = 3;</code>

@return This builder for chaining.
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeLongAudioMetadata.java