Does anyone know of a way to mock a web service while specifying latency and throughput?

In order to to experiment with error handling and back-off strategies in a typical "micro-services" architecture, I would like to have a simple "mock" web service that

• has configurable latency and throughput, changeable at runtime
• can handle some thousands of requests per second on cheap hardware

Does anyone know of such a thing?

Thanks in advance.