appendInputAudio(arrayBuffer) {
    if (arrayBuffer.byteLength > 0) {
      this.realtime.send('input_audio_buffer.append', {
        audio: RealtimeUtils.arrayBufferToBase64(arrayBuffer),
      });
      this.inputAudioBuffer = RealtimeUtils.mergeInt16Arrays(
        this.inputAudioBuffer,
        arrayBuffer,
      );
    }
    return true;
  }
Appends user audio to the existing audio buffer
@param {Int16Array|ArrayBuffer} arrayBuffer
@returns {true}