Method setupWebSocketHandler

packages/next/src/server/next.ts:430–444

(
    customServer?: import('http').Server,
    _req?: IncomingMessage
  )

  }

  private setupWebSocketHandler(
    customServer?: import('http').Server,
    _req?: IncomingMessage
  ) {
    if (!this.didWebSocketSetup) {
      this.didWebSocketSetup = true
      customServer = customServer || (_req?.socket as any)?.server

      if (customServer) {
        customServer.on('upgrade', async (req, socket, head) => {
          this.upgradeHandler(req, socket, head)
        })
      }
    }
  }

  getRequestHandler(): RequestHandler {
    return async (