While setting up the OS X build, I encountered a funny issue. Running ulimit -n 4096 inside PowerShell had no effect, so I had to run it before launching the PowerShell process. Now, ulimit is both a Bash built-in and a native command on OS X. My guess is that, when running from PowerShell, it was launched as a child process (of course) and so the system call to setrlimit only affected the launched child process, not PowerShell itself.

I think the appropriate fix would be to add a built-in ulimit function to PowerShell that called setrlimit in-proc, thus modifying the current process's open file descriptor limit.

This is a total edge case that we should take care of at some point, but I don't think it's super high priority.