public Builder mergeInput(com.google.cloud.texttospeech.v1.StreamingSynthesisInput value) {
      if (inputBuilder_ == null) {
        if (streamingRequestCase_ == 2
            && streamingRequest_
                != com.google.cloud.texttospeech.v1.StreamingSynthesisInput.getDefaultInstance()) {
          streamingRequest_ =
              com.google.cloud.texttospeech.v1.StreamingSynthesisInput.newBuilder(
                      (com.google.cloud.texttospeech.v1.StreamingSynthesisInput) streamingRequest_)
                  .mergeFrom(value)
                  .buildPartial();
        } else {
          streamingRequest_ = value;
        }
        onChanged();
      } else {
        if (streamingRequestCase_ == 2) {
          inputBuilder_.mergeFrom(value);
        } 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