Martin Panter added the comment:
The general problem of non-blocking reads with BufferedIOBase is covered by
Issue 13322. The documentation and implementations do not agree. I suggest to
not rely on any particular behaviour reading BufferedIOBase objects in
non-blocking mode.
The problem of
New submission from Cyker Way :
Document of
[BufferedIOBase](https://docs.python.org/3/library/io.html#io.BufferedIOBase)
says:
> ...unlike their RawIOBase counterparts, they will never return None.
But this example shows the above statement is not true:
import io
import os
