In article <200311221025.18309.transami / runbox.com>,
  "T. Onoma" <transami / runbox.com> writes:

> Wouldn't that download the whole file?

Use :progress_proc you suggested.

t1 = Time.now
open("http://...", :progress_proc => lambda {|size| p size / (Time.now - t1) }) {}

No option needed which is dedicated for connection speed.
-- 
Tanaka Akira