from experience, during bursts it's never actual web/api server that is bogged down, it's the downstream io bottlenecks.
if your accepting layer is abstracted away and implemented correctly, there is very little performance difference between different concurrency approaches and all you're exposed to as developer is implementation of your handler functions.
if your accepting layer is abstracted away and implemented correctly, there is very little performance difference between different concurrency approaches and all you're exposed to as developer is implementation of your handler functions.