Setting up channel_log during replay

[zohassadar]

I was using the channel_log feature to scrape banner output and found that when running in a test, the driver.channel.channel_log was set to None instead of the BytesIO object expected. This looks to be the result of the channel's open method never getting called.

I was able to get the behavior I was looking for by calling cls.channel.open() within the patched open method. The code shown in this commit. I added a list for close callbacks to allow for future callbacks to be added, but this might be an overcomplication. If this is a desirable feature to keep around, I can submit a pull request.

[carlmontanari]

hey @zohassadar 👋

interesting! -- are you basically testing the contents of the channel log too and thats why ya need it there?

It's been far too long since I looked at this but I guess this must just have been an oversight. If you wanna put a quick pr together we can get that merged in! Regarding the close callbacks: probably unnecessary... what other things to close do you think would pop up?

[zohassadar]

Yup, exactly. The channel_log is a great feature.

I simplified the closing and put in a PR.