`requestHandler` receives the continuation - is there a situation where that's necessary?

To my understanding, for any request, the server is to invoke the continuation that produces the response exactly once - so why does `lsp` not do that by itself? It seems unnecessary to give the user the freedom to drop the continuation or even invoke it multiple times.
I guess one could indeed come up with an example where you want to put the continuation in a work queue or something like that but I expect that `lsp` itself should have better insight on when to actually invoke the continuation than any user of the library? Or you could just provide a hook where all IO actions that fire a response go through?