When holding the right scroll-bar in the Windows console (to study the
verbose output etc.), the network I/O freezes as shown in attached I/O-graph.
(big dips in the recv-rate) I tested this with FTP-recv and a 390 MByte file:
  curl.exe -v -o NUL ftp://ftp.uib.no/pub/users/hmifs/Making%20rain.m4v

There seems to be an "easy" fix for the network I/O freeze. Here are some
suggestions:
  http://stackoverflow.com/questions/14837941/holding-scroll-bar-gets-command-prompt-to-pause-in-windows

1. use a separate thread for doing all the network I/O. (let console output be blocked).
2. or intercept WM_VSCROLL.

Fix 1 is similar to how 'wget --background' does it (in mswindows.c::fake_fork).
Or one can press '^Break' to force Wget to go into background. But then Wget
does *all* I/O in the background (it creates a separate child *process*). So maybe
having network I/O in a separate *thread* would be the easiest to implement?

Would it make sense to do something similar for curl? Someone else having some
ideas on this?

---gv

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