Victor> About Python3, os.popen() is more than two times faster (0.20
    Victor> sec vs 0.50 sec) than subprocess.Popen()! It's amazing because
    Victor> popen() opens the standard output as unicode file whereas
    Victor> Popen() creates a binary file! Another funny thing: os.popen()
    Victor> calls subprocess.Popen() :-) The difference is just this
    Victor> instruction:
    Victor>    stdout = io.TextIOWrapper(stdout)

This is a known issue.  The default for bufsize in os.popen is -1 (fully
buffered? line buffered?).  The default for bufsize in subprocess.Popen is 0
(unbuffered).  I think it should have been changed but was voted down.  I
think the best you can do at this point is document the change, perhaps in
the "Replacing os.popen" section.

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