src/node/plugin.ts/PluginAPI/_loadPlugins
class PluginAPI:  private async _loadPlugins(dir: string): Promise<void> {
    try {
      const entries = await fsp.readdir(dir, { withFileTypes: true })
      for (const ent of entries) {
        if (!ent.isDirectory()) {
          continue
        }
        await this.loadPlugin(path.join(dir, ent.name))
      }
    } catch (error: any) {
      if (error.code !== "ENOENT") {
        this.logger.warn(`failed to load plugins from ${q(dir)}: ${error.message}`)
      }
    }
  }