How to use react-unity-webgl - 1 common examples

constructor(props) {
    super(props);
    this.speed = 30;
    this.state = { rotation: 0, unityShouldBeMounted: true };

    this.unityContent = new UnityContent(
      "unity_project_build/Build.json",
      "unity_project_build/UnityLoader.js"
    );

    this.unityContent.on("Say", message => {
      console.log("Wow Unity said: " + message);
    });

    this.unityContent.on("SendRotation", rotation => {
      this.setState({ rotation: Math.round(rotation) });
    });

    this.unityContent.on("progress", progression => {
      console.log("Unity progress", progression);
    });