@java.lang.Override
    public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
      return super.setUnknownFields(unknownFields);
    }
<pre>
Input to synthesize. Specified in all messages but the first in a
`StreamingSynthesize` call.
</pre>

<code>.google.cloud.texttospeech.v1.StreamingSynthesisInput input = 2;</code>
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/StreamingSynthesizeRequest.java