Nim attempts to at least partially resolve this via the {.multisync.} pragma. It's functionally equivalent to {.async.} but means that the compiler also generat

Nim attempts to at least partially resolve this via the {.multisync.} pragma. It's functionally equivalent to {.async.} but means that the compiler also generates code for synchronous IO, this is what enables the stdlib to implement an HttpClient and AsyncHttpClient with little to no duplication. Of course, the downside is that it relies on library authors to use this mechanism.