public Builder setInput(com.google.cloud.texttospeech.v1.StreamingSynthesisInput value) {
      if (inputBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        streamingRequest_ = value;
        onChanged();
      } else {
        inputBuilder_.setMessage(value);
      }
      streamingRequestCase_ = 2;
      return this;
    }
<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