private void ensureTurnsIsMutable() {
      if (!((bitField0_ & 0x00000001) != 0)) {
        turns_ =
            new java.util.ArrayList<com.google.cloud.texttospeech.v1.MultiSpeakerMarkup.Turn>(
                turns_);
        bitField0_ |= 0x00000001;
      }
    }
<pre>
A collection of turns for multi-speaker synthesis.
</pre>

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