Method constructor

tfjs-layers/src/engine/training_test.ts:1403–1409

(readonly recordedParams: Params[])

  class CustomCallbackForTest extends tfl.CustomCallback {
    constructor(readonly recordedParams: Params[]) {
      super({
        onTrainBegin: async () => {
          recordedParams.push(this.params);
        }
      });
    }
  }

  it('Custom callback params: no validation', async () => {