title: Can Haskell's Control.Concurrent.Async.mapConcurrently have a limit?
body: <p>I'm attempting to run multiple downloads in parallel in Haskell, which I would normally just use the Control.Concurrent.Async.mapConcurrently function for.  However, doing so opens ~3000 connections, which causes the web server to reject them all.  Is it possible to accomplish the same task as mapConcurrently, but only have a limited number of connections open at a time (i.e. only 2 or 4 at a time)?</p>