Add an async open() method which should allow to do what __init__()
couldn't, because it's not async, and to match the already existing
.close(). It's called by __aenter__() __aexit__() if the FileContext
is instantiated as context manager, or at will when the user finds it
a good idea.
Signed-off-by: Jan Lindemann <jan@janware.com>
Jan Lindemann
58f7997bc6