Add a comment explaining why SocketIO is needed
diff --git a/Lib/socket.py b/Lib/socket.py
index 9b5b23d..2861e0d 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -228,6 +228,13 @@
the raw I/O interface on top of a socket object.
"""
+ # One might wonder why not let FileIO do the job instead. There are two
+ # main reasons why FileIO is not adapted:
+ # - it wouldn't work under Windows (where you can't used read() and
+ # write() on a socket handle)
+ # - it wouldn't work with socket timeouts (FileIO would ignore the
+ # timeout and consider the socket non-blocking)
+
# XXX More docs
def __init__(self, sock, mode):