Function runSsg

runSsg(
    options: {
        concurrency?: number;
        definitions: RouteDefinitionLike[];
        extraTargets?: PrerenderTarget[];
        onSkipped?: (skipped: SkippedTargets) => void;
        outDir?: string;
        params?: SsgParams;
        render: (target: PrerenderTarget) => Promise<PrerenderResult>;
    },
): Promise<string[]>
Run the full SSG pass: collect targets, render each, write files.

The render function is supplied by the build pipeline (it invokes the built SSR app / use-react's prerenderPage for a given path). Rendering runs with bounded concurrency.
Parameters
- options: {
      concurrency?: number;
      definitions: RouteDefinitionLike[];
      extraTargets?: PrerenderTarget[];
      onSkipped?: (skipped: SkippedTargets) => void;
      outDir?: string;
      params?: SsgParams;
      render: (target: PrerenderTarget) => Promise<PrerenderResult>;
  }
  Orchestration options.
Returns Promise<string[]>
The list of written file paths.