public Builder clearInputSource() {
      inputSourceCase_ = 0;
      inputSource_ = null;
      onChanged();
      return this;
    }
<pre>
Input to be synthesized.
</pre>

Protobuf type {@code google.cloud.texttospeech.v1.StreamingSynthesisInput}
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/StreamingSynthesisInput.java