Method registerBackend

tfjs-core/src/engine.ts:260–272

(
      backendName: string,
      factory: () => KernelBackend | Promise<KernelBackend>,
      priority = 1)

  }

  registerBackend(
      backendName: string,
      factory: () => KernelBackend | Promise<KernelBackend>,
      priority = 1): boolean {
    if (backendName in this.registryFactory) {
      log.warn(
          `${backendName} backend was already registered. ` +
          `Reusing existing backend factory.`);
      return false;
    }
    this.registryFactory[backendName] = {factory, priority};
    return true;
  }

  async setBackend(backendName: string): Promise<boolean> {
    if (this.registryFactory[backendName] == null) {